Uncinaria americana and Agchylostoma duodenale cause in man the disease variously known as uncinariasis, uncinariosis, anchylostomiasis, tunnel disease, miners' anemia, brickmakers' anemia, mountain anemia, etc.

Agchylostoma caninum [Uncinaria canina"] causes a similar disease in dogs, resulting, in some parts of the country, in a death rate of from 25 to 40 per cent of the pups born. Uncinariasis in dogs is exceedingly common in Washington, D. C. "Typhoid" in cats is attributed to this parasite.

Instructors in medical colleges who wish to demonstrate hookworms and their eggs to the students will find A. caninum of dogs an excellent substitute for Agchylostoma duodenale of man in case the latter species can not be obtained.

Uncinaria stenocephala occures in dogs, foxes, and allied animals, and is causing considerable trouble in the blue fox (Vulpes lagopus) industry.

Uncinaria trigonocephala' is found in sheep and produces a serious anemia. This parasite has been met in Victoria and Calhoun counties, Tex., where, in conjunction with the twisted wireworm (Hæmonchus contortus), it has caused the death of from 25 to 50 per cent of certain flocks.

Uncinaria radiata is found in cattle, producing trouble just below the stomach. The writer has collected this parasite in Dewitt, Gonzales, Victoria, and Calhoun counties, Texas, and has seen specimens from Florida collected by Dr. C. F. Dawson.

Uncinaria Lucasi was found several years ago in the seal pups of Alaska by Mr. Lucas, after whom the worm has been named. It is responsible for about 17 per cent of the deaths of the pups.

Still other species of hookworms are reported for other animals. None of the species from animals mentioned above is known to affect man, nor has either Uncinaria americana or Agchylostoma duodenale of man been satisfactorily demonstrated to occur normally in other hosts than man.

aThis is Uncinaria canina (Ercolani 1859) Railliet, 1900, a parasite of canines and felines, which is usually known as Uncinaria trigonocephala (Rudolphi, 1809) Railliet, 1885 [not Uncinaria trigonocephala (Rudolphi, 1809) Railliet, 1900]. If Uncinaria and Agchylostoma are recognized as distinct, U. canina should be placed in the same genus as U. duodenalis. I have not yet tested the correctness of the specific name canina for this form, but it is here accepted on authority of Railliet.

This is Uncinaria trigonocephala (Rudolphi, 1809) Railliet, 1900 [not “U. trigonocephala Rudolphi, 1809)" Railliet, 1885]. Both Railliet and I have recently examined Rudolphi's original material, and it is unquestionably identical with U. cernua (Creplin, 1829) of sheep. This species is closely related to U. americana. e Strongylus contortus Rudolphi.

d Bunostomum phlebotomum Railliet.

3044-No. 10—03- -2

FIG. 2.-New World male hookworm (Uncinaria americana). Natural size. (After Stiles, 1902b, p. 190, fig. 120.)

FIG. 3.-New World female hookworm (Uncinaria americana). Natural size. (After Stiles, 1902b, p. 190, fig. 121.)

FIG. 4.-The same, enlarged to show the position of the anus (a) and the vulva (v). After Stiles, 1902b, p. 190, fig. 122.)

FIG. 5.-Dorsal view of anterior end of New World hookworm (Uncinaria americana): b. c., buccal cavity; c. p., cervical papillæ; d. m. t., dorsal median tooth, projecting prominently into the buccal cavity; d. sm. l., small dorsal semilunar lip; e., esophagus; m. m., margin of mouth, the prominent oval opening seen upon high focus: p. p., papillæ; v. sm. l., large ventral semilunar lips homologous with the ventral hooks of 4. duodenale. Greatly enlarged. (After Stiles, 1902b, p. 190, fig. 123.) FIG. 6.-Lateral view of anterior end of New World hookworm (Incinaria americana): b. c., buccal cav ity; d. m. t., dorsal median tooth, projecting prominently into buccal cavity; e., esophagus; m. m., margin of mouth; p. p., papillæ; d. l., dorsal lancet; v. l., ventral lancets at the base of the buccal cavity. Greatly enlarged. (After Stiles, 1902b, p. 190, fig. 124.)

FIG. 7.-Lateral view of caudal bursa of the New World male hookworm (Uncinaria americana), showing the arrangement of the rays. Note the short dorsal lobe. Greatly enlarged. (After Stiles, 19025, p. 190, fig. 125.)

tip of tail. FIG. 8.-The caudal end of the New World male hookworm (Uncinaria americana). The bursa is spread out to show the arrangement of the rays. Note the short dorsal lobe which is subdivided, forming two lobes; note also the indistinct ventral lobe connecting the two lateral lobes. The dorsal lobe is thrown back over the body. [Additional material shows that the "barb" or tip of the spicules as drawn is not quite correct.] Greatly enlarged. (After Stiles, 1902b, p. 191, fig. 126.) [UNCINARIA Froelich, 1789, sensu stricto.] DIAGNOSIS.-Uncinaria s. 1. with buccal lips.

TYPE SPECIES.-Uncinaria vulpis Froelich.

The New World hookworm-UNCINARIA AMERICANA" Stiles, 1902-of man.

SPECIFIC DIAGNOSIS.- Uncinaria: Body cylindrical, somewhat attenuated anteriorly. Buccal capsule with a ventral pair of prominent semilunar plates or lips, similar to U. stenocephala, and a dorsal pair of slightly developed lips of the same nature; dorsal conical median tooth projects prominently into the buccal cavity, similar to Monodontus; one pair of dorsal and one pair of ventral submedian lancets deep in buccal capsule. Male, 7 to 9 mm. long; caudal bursa with short dorso-median lobe, which often appears as if it were divided into two lobes, and with prominent lateral lobes united ventrally by an indistinct ventral lobe; for rays, see figures 7-8; common base of dorsal and dorso-lateral rays very short; dorsal ray divided to its base, its two branches being prominently divergent and their tips being bipartite; spicules long and slender. Female, 9 to 11 mm. long; vulva in anterior half of body, but near equator. Eggs, ellipsoid, 64 to 76 u long by 36 to 40 μ broad, in some cases partially segmented in utero, in other (rare) cases containing a fully developed embryo when oviposited.

HABITAT.-Small intestine of man (Homo sapiens) in America (determined to date, for Virginia, North and South Carolina, Georgia, Florida, Alabama, Texas, Porto Rico, Cuba, and Brazil).

TYPE SPECIMENS.-No. 3310, B. A. I., U. S. Dept. Agric.

a SYNONYMY WITH ORIGINAL PLACE OF PUBLICATION.

1902: Uncinaria americana STILES <Am. Med., Phila., v. 3 (19), May 10, pp.777-778. 1902: Unicinaria americana (Stiles) VON LINSTOW Zool. Centralbl., Leipz., v. 9 (24-25), 16. Dec., p. 778. [Misprint.]

LIFE HISTORY OF UNCINARIA AMERICANA.

The life history of the American hookworm has not yet been determined in detail, but there is no reason for assuming that it will differ radically from that of Agchylostoma duodenale (see p. 24.)

In my first description of the worm I stated that the egg in the uterus may occasionally contain an embryo. Since making this observation on the females sent to me by Dr. Allen J. Smith I have examined hundreds of fresh eggs, but have not found any containing

developed embryos. The question may therefore legitimately arise whether the females originally examined were not exposed to the air for some time before they were preserved, thus making the development of the eggs possible. If the embryo does develop in the uterus, as indicated by some of Dr. Allen J. Smith's material, such an occurrence is undoubtedly rare.

DEVELOPMENT OUTSIDE THE BODY.

Segmentation. In feces exposed to a September, October, or early November

FIG. 9.-Four eggs of the New World temperature of the Carolinas, Georgia,

hookworm, Uncinaria americana, in the 1, 2, and 4 cell stages. The egg showing 3 cells is a lateral view of a 4-cell stage. These eggs are found in the feces of patients and give a positive diagnosis of infection. Greatly enlarged. (After Stiles, 1902b, p. 192, fig. 127.)

and Florida, the embryo develops in the egg (fig. 9) in about one day's time. In some instances the embryo develops in less than 24 hours. It is a common occurrence to find feces 24 hours old containing free embryos.

The conditions under which the trip was made were not favorable to exact observation in regard to temperature, moisture, etc. It was, however, possible to find worms in their first ecdysis about 2 to 3 days after hatching, and worms in the second ecdysis about 7 to 9 days after hatching. These observations were made under most unfavorable circumstances, when careful measurements, drawings, etc., were excluded, hence they should be repeated.

DEVELOPMENT INSIDE THE BODY.

Experimental infections during the trip were, of course, impossible.

[AGCHYLOSTOMA @ Dubini, 1843.]

DIAGNOSIS.-Uncinaria: Provided with ventral recurved teeth.

TYPE SPECIES.—Agchylostoma duodenale Dubini, 1843.

The Old World hookworm-AGCHYLOSTOMA DUODENALE Dubini, 1843, or UNCINARIA DUODENALIS (Dubini) Railliet, 1885—of man.

(Figures 10 to 41.)

SPECIFIC DIAGNOSIS.—Agchylostoma: Body cylindrical, somewhat attenuated anteriorly. Buccal cavity with two pairs of ventral teeth curved like hooks, and one pair of dorsal teeth directed forward; dorsal rib not projecting into the cavity. Male, 8 to 11 mm. long; caudal bursa with dorso-median lobe, and prominent lateral lobes united by a ventral lobe; for rays, see fig. 14; dorsal ray divides at a point two-thirds its length from its base, each branch being tridigitate; spicules long and slender. Female, 10 to 18 mm. long; vulva at or near posterior third of body. Eggs, ellipsoid, 52 to 60 μ by 32 μ, laid in segmentation. Development direct without intermediate host.

❝ There are numerous ways of spelling this word (see p. 15), more than one with more or less philological authority. Under these circumstances I adopt the original orthography, despite the fact that it is not philologically correct. By this action I do not intend to necessarily reject the ruling covered by the International Code, but from practical experience I find it impracticable to carry out said rule in reference to the emendation of names until the question of homonyms is decided.

SYNONYMY, WITH ORIGINAL PLACE OF PUBLICATION.

1843: Agchylostoma duodenale DUBINI <Ann. univer. di med., Milano, v. 106, aprile, pp. 5-13, pl. 1, figs. 1-5; pl. 2, figs. 1-3.

1845: Ancylostoma duodenale (Dubini) CREPLIN <Arch. f. Naturg., Berl., 11. J., v. 1, p. 325.

(1846): Anchylostoma duodenale (Dubini) DELLE CHIAJE <Rendicon. dell' Accad. delle sci., Napoli, v. 5, p. 339. [Not verified.]

1850: Anchylostoma duodenale (Dubini) DUBINI, Entozoografia umana, pp. 103–112. 1851: Anchylostomum duodenale (Dubini) DIESING, Systema helminthum, v. 2, p. 322. ?(1851): Strongylus quadridentatus SIEBOLD <Naturforsch. Versamml. z. Gotha. [Not verified.]

1861: Dochmius anchylostomum MOLIN, Il sottordine degli acrofalli <Mem. r. Ist. ven. di sc., lett. ed arti, Venezia, v. 9, pp. 485–487.

1864: Sclerostoma duodenale (Dubini) COBBOLD, Entozoa, pp. 361–362, fig. 77. 1866: Strongylus duodenalis (Dubini) SCHNEIDER, Monographie der Nematoden, Berl., pp. 139-140, 1 fig., pl. 9, fig. 3.

1866: "Ancylostomum duodenate Dubini" of WHITE <Boston M. & S. J., v. 75 (21), Dec. 20, p. 427. [Misprint for duodenale.]

1876: Dochmius duodenalis (Dubini) LEUCKART, Die menschlichen Parasiten, v. 2 (3), pp. 410-460, figs. 235-239, 241-247, 249.

1879: Anchilostoma duodenale (Dubini) BozZOLO (Osservatore, Torino, v. 15 (24), 17 giugno, pp. 369–370.

1881: Docmius duodenalis <Rev. méd. de la Suisse Rom., Genève, v. 1 (3), 15 mars, p. 190.

1885: Uncinaria duodenalis (Dubini) RAILLIET, Éléments de zool. méd. et agric., Par., pp. 357-359, figs. 245-248.

1897: Anchylostamum duodenale (Dubini) MŒHLAU <Buffalo M. J., v. 36 (8), Mar., pp. 573-579. [Misprint for Anchylostomum duodenale.]

Ankylostoma duodenale and Ankylostomum duodenale of various authors.