other than the family of cats themselves (Felida), we may now contrast the latter (i.e., the Felida,) with each of the former. The different kinds of cats all agree with the common cat in Fig. 207.-PART OF THE BASE OF THE SKULL OF THE TIGER (Felis tigris). am. Meatus auditorius externus. c. Condyloid foramen. car. Carotid foramen. e. Eustachian canal. 1. Foramen lacerum posterius. m. Mastoid process. o. Foramen ovale. p. Par-occipital process r. Fenestra rotun !a. A PORTION OF THE THE CAVITY OF THE s. Septum between the chambers. structure, save as regards the details already pointed out in the last chapter. We may then proceed to sum up the main points in which the cat's FAMILY differs from the other three families of the suborder Eluroidea, as follows. The FELIDE differ from the VIVERRIDE, in that in the Felida: (1) The bead is more rounded; (2) The limbs are generally longer in proportion to the trunk; (3) The claws are generally more completely retractile ; (4) The teeth are more sectorial, and the premolars and tubercular molars are fewer, there being never more than one tubercular molar (an upper one) in any living species; (5) There are no conspicuous scent-glands; (6) There is no ali-sphenoid canal save in certain extinct genera; (7) The division of the bulla is hardly perceptible exteriorly, while the two chambers into which it is internally divided are not placed one quite behind the other; (8) The carotid foramen is always very small, and the carotid canal indistinct, except in some extinct genera; Fig. 208.-SECTION OF THE AUDITORY BULLA OF THE TIGER (Flower). am. Meatus auditorius externus. BO. Basi-occipital, e. Eustachian canal. ic. The inner chambers. o c. The outer chamber. * The aperture of communication between the chambers. Pt. Petrosal. s. Septum. Sq. Squamosa (9) The par-occipital process (though applied to the bulla) may, in large species, develope a marked process; (10) The meatus auditorius externus is never medianly fissured below. The FELIDE differ from the HYENIDE in that: (1) Their head is more rounded; (2) Their claws are retractile; (3) The body does not droop so much posteriorly; (4) The teeth are more perfectly sectorial in form; (5) The premolars are less numerous; (6) The bulla is, at least in existing species, divided into two chambers, which are not placed completely one behind the other; (7) The bulla is most prominent towards its inner, not towards its hinder border; (8) The bony meatus auditorius externus is not produced anteriorly into an outstanding process; (9) There may be a small bone to the penis; (10) There are no conspicuous scent-glands; (11) There are only thirteen dorsal vertebræ. The FELIDE differ further from the TRUE HYENAS (ie, the Hyænas as distinguished from Proteles) in that: (1) Their teeth are less powerfully formed for crushing; (2) The bulla is divided by a septum ; (3) The carotid foramen is generally still less conspicuous. They further differ from Proteles in that: (1) Their teeth are much stronger and larger relatively, and more closely approximate; (2) The chambers of the bulla are not quite one behind the other. The FELIDE differ from the CRYPTOPROCTIDE in that: (1) They are quite digitigrade; (2) Their skull is relatively shorter and rounder; (3) Their premolars are (except in Archælurus) less numerous; (4) The chambers of the bulla are not quite one behind the other; (5) There is no ali-sphenoid canal, save in some extinct genera; (6) The supra-condyloid foramen is of moderate size; (7) The metacarpals and metatarsals are relatively longer; (8) The pollex is very small, and the hallux a mere rudiment; (9) The naked pads of the feet are much less extended; (10) The bone of the penis is small. § 25. We have now before us as complete a statement as the author can give of the relations which exist between the cat's family and all other living organisms whatsoever. As to the subordinate groups contained within the cat's own family, i.e., its genera, we saw in the last chapter that all known cats living and extinct can be arranged in eleven sets of kinds, to which the names Felis, Cynælurus, Elurodon, Archælurus, Dinictis, Nimravus, Pseudælurus, Hoplophoneus, Pogonodon, Macharodus, and Eusmilus, have been given. We now see what was meant by saying that these groups have each the value of a "genus." As to the relations which exist between the feline genera, we now also see that the exceptional characters presented by Dinietis and Archælurus are peculiarities which cause those genera to have a certain resemblance to the Viverrine family. In the last chapter we recognized the fact that an extreme specialization of structure is presented by Machærodus and Eusmilus, and that Cynælurus is the most exceptional form amongst living felines, and one in which some of the distinctive characters of its family (e.g., the retractility of the claws), are poorly developed. The cat's genus, Felis, is one which, while it well exemplifies the characters of the family to which it belongs, yet does not exhibit any of those characters developed either in an extreme or in an aberrant manner. This statement needs some explanation. Every group of animals containing various species consists of certain kinds, which are more or less alike, and differ but little from an ideal standard which is the type of such group. Such kinds are normal forms. Besides these, there are generally certain other kinds which are peculiarly modified in one way or another, departing more or less widely from the normal structure. Such divergent kinds are said to be aberrant or abnormal. Also both "normal" and "aberrant" forms may be either what is called specialized or generalized. "Specialized " creatures are such as have an exceptional organization of a definite kind. "Generalized" creatures are such as resemble the general run of animals to which they are more or less closely related, but have the distinctive characters of their group poorly developed. But besides the specialized and generalized normal forms, there may be other normal forms which are neither of these, but adhere closely to the type and express it in its intensity, yet without any one-sided development of it. These are TYPICAL FORMS. The full meaning of these terms can only be made clear by examples, for which it is necessary to refer to some other group of animals with which the reader may be acquainted, or with which he can easily become so. Let us then take, as examples, species of the well-defined group of ruminating beasts. Amongst them we have creatures which adhere to the normal structure, but yet its characteristic features are in them but poorly developed. They are then generalized normal forms, as, e.g., that small South American deer, the yenada or pudu (Pudu humilis). Others, which adhere to the normal structure, may carry it to an intense but somewhat one-sided degree of development. Such would be specialized normal forms, as, e.g., the elk or the four-horned antelope. Others again may diverge from the general type in the direction of other creatures outside their group. Such would be generalized aberrant forms, such as the camel and llama, or as the chevrotains; whilst others may diverge from such type in a special direction of their own, and such would be called specialized aberrant forms, as, e.g., the giraffe. Finally, others will be normal, and yet with the characters special to the group strongly developed, i.e., they will be typical forms, as, e.g., the red deer or the Indian antelope. To apply these remarks to the Felida, we have an example of a "generalized normal form " in the cheetah, Cynælurus. The lion is an example of a "specialized normal form." For a "generalized aberrant form" we must have recourse to fossils, such as Dinictis, and, above all, Archælurus, as also for specialized aberrant forms, of which Eusmilus and Machærodus smilodon afford us excellent examples. Finally, as the expression of the typical or fully-developed normal form of the cat's family, we have the species which go to make up the maneless cats of the typical genus Felis, of which Felis catus will stand as a very good example. But if the cat is thus the typical genus of its family, in what relation may its family be said to stand to the other families of its order thus considered? Of all the families of that order, the dog's family, Canide, seems to be the most generalized aberrant one. For while it possesses the general characters of its order without carrying them to an intense degree, it shows certain resemblances to forms outside its order.* The bears, on the other hand, are specialized aberrant forms, as they depart from the normal standard of the order in a special direction of their own, as also do the otters and several other forms of Carnivora.t As to the mass of the Mustilida and Viverridæ, they may be considered to be normally generalized carnivores, since they possess the ordinary carnivorous characters moderately developed. It is not easy to point out any certainly normally specialized families-any family, that is, which has the characters of the order in an intense degree, but developed, as it were, in a one-sided manner. Such characters seem only present in certain exceptional Felidæ, such as Macharodus and Eusmilus. If so, then the Felida, as a whole, must be held to be the typical family of the whole order; for they carry the carnivorous type of structure to an intense degree, but one which is in the direct line of development which the order Carnivora has followed. Carnivorous beasts generally have sharp claws, often more or less retractile, but none have them so perfectly developed in these respects as have the cats. Almost all carnivorous beasts have teeth more or less well adapted for killing prey and cutting flesh, but none have their teeth so admirably adapted for these purposes as have the cats. The cats are then carnivora par excellence, and they carry out the type of their order to its highest-known and most perfectly harmonious expression. But the cats are not only such highly-developed Carnivora. Something may also be said in favour of their being the highest of mammals-the very flower and culmination of the mammalian animal tree. Spontaneous activity and sensitiveness are the special characteristics of animal life, and with both these powers the cats are largely endowed. We have recognized the perfection of their organs of movement, and that of the very substance of their bones and muscles, as well as the great perfection of their special senses. It may be objected, however, that the activities and sense perceptions of certain other beasts E.g., to certain marsupials. Such as e.g. the kinkajou (Cerco leptes), the binturong (Arctitis), and also Proteles. |