Page:EB1911 - Volume 23.djvu/157

Rh into five “sense” series, and each series into three orders, one comprising forms of superior, the second of medium and the third of inferior development. In the generic arrangement of the species, to which Fitzinger devoted himself especially in this work, he equally failed to advance science.

We have now arrived at a period distinguished by the appearance of a work which superseded all its predecessors, which formed the basis for the labours of many succeeding years, and which will always remain one of the classical monuments of descriptive zoology—the Erpétologie générale ou histoire

naturelle complète des reptiles of and and (Paris, 8vo). The first volume appeared in 1834, and the ninth and last in 1854. No naturalist of that time could have been better qualified for the tremendous undertaking than C. Duméril, who almost from the first year of half a century's connexion with the then largest collection of Reptilia had chiefly devoted himself to their study. The task would have been too great for the energy of a single man; it was, therefore, fortunate for Duméril that he found a most devoted fellow-labourer in one of his assistants, G. Bibron, whose abilities equalled those of the master, but who, to the great loss of science, died (in 1848) before the completion of the work. Duméril had the full benefit of Bibron's knowledge for the volumes containing the Snakes, but the last volume, which treats of the Tailed Batrachians, had to be prepared by Duméril alone.

The work is the first which gives a comprehensive scientific account of reptiles generally, their structure, physiology and literature, and again each of the four orders admitted by the authors is introduced by a similar general account. In the body of the work 121 Chelonians, 468 Saurians, 586 Ophidians and 218 Batrachians are described in detail and with the greatest precision. Singularly enough, the authors revert to Brongniart's arrangement, in which the Batrachians are co-ordinate with the other three orders of reptiles. This must appear all the more strange as Von Baer in 1828, and J. Müller in 1831, had urged, besides other essential differences, the important fact that no Batrachian embryo possesses either an amnion or an allantois, like a reptile.

4. Period of the Separation of Reptiles and Batrachions as Distinct Classes or Subclasses.—In the chronological order which we have adopted for these historical notes, we had to refer in their proper places to two herpetologists, Blainville and Latreille, who advocated a deeper than merely ordinal separation of Reptiles from Batrachians, and who were followed by

F. S. Leuckart. But this view only now began to find and more general acceptance. and were guided in their classification entirely by anatomical characters, and consequently recognized the wide gap which separates the Batrachians from the Reptiles; yet they considered them merely as subclasses of the class Amphibia. The former directed his attention particularly to those forms which seemed to occupy an intermediate position between Lacertilians and Ophidians, and definitely relegated Anguis, Pseudopus, Acontias to the former, and Typhlops, Rhinophis, Tortrix, but also the Amphisbaenoids to the latter. Stannius interpreted the characteristics of the Amphisbaenoids differently, as will be seen from the following abstract of his classification: —

. 1. STREPTOSTYLICA (Stann.). Quadrate bone articulated to the skull; copulatory organs paired, placed outside the cloacal cavity. 1. OPHIDIA. Subordo 1. or (Müll.). The facial bones are loosely connected to admit of great extension of the wide mouth. Subordo 2. or (Müll.). Mouth narrow, not ex tensile; quadrate bone attached to the skull and not to a mastoid. 2. SAURIA. Subordo 1. . Subordo 2. (Stann.) = Lizards. Subordo 3. . . 2. MONIMOSTYLICA (Stann.). Quadrate bone suturally united with the skull; copulatory organ simple, placed within the cloaca. 1. CHELONIA. 2. CROCODILIA.
 * AMPHIBIA MONOPNOA (Leuckart).

This classification received the addition of a fifth Reptilian order which with many Lacertilian characters combined important Crocodilian affinities, and in certain other respects differed from both, viz. the New Zealand Hatteria, which by its first describers had been placed to the Agamoid Lizards. , who pointed out the characteristics of this reptile, considered it to be co-ordinate with the other four orders of reptiles, and characterizes it thus:—

Rhynchocephalia.—Quadrate bone suturally and immovably united with the skull and pterygoid; columella present. Rami of the mandible united as in Lacertilians. Temporal region with two horizontal bars. Vertebrae amphicoelian. Copulatory organs, none.

5. Period of the Recognition of a Class of Reptilia as Part of the Sauropsida.—Although so far the discovery of every new morphological and developmental fact had prepared naturalists for a class separation of Reptiles and Batrachians, it was left to T. H. Huxley to demonstrate, not merely that the weight of facts demanded such a class separation, but that the reptiles hold the same relation to birds as the fishes to Batrachians. In his Hunterian Lectures (1863) he divided the vertebrates into Mammals, Sauroids and Ichthyoids, subsequently substituting for the last two the terms Sauropsida and Ichthyopsida. The Sauropsida contain the two classes of birds and reptiles, the Ichthyopsida those of Batrachians and fishes.

6. Period of the Consideration of Skeletons of Extinct Reptiles.—, while fully appreciating the value of the osteological

characters on which Huxley based his division, yet admitted into his consideration those taken from the organs of circulation and respiration, and reverted to Latreille's division of warm- and cold-blooded (haematothermal and haematocryal) vertebrates, thus approximating the Batrachians to reptiles, and separating them from birds. The reptiles (or Monopnoa, Leuck,) thus form the highest of the five subclasses into which, after several previous classifications, Owen finally divided the Haematocrya. His division of this subclass, however, into nine orders, makes a considerable step in the progress of herpetology, since it takes into consideration for the first time the many extinct groups whose skeletons are found fossil. He shows that the number of living reptilian types bears but a small proportion to that of extinct forms, and therefore that a systematic arrangement of the entire class must be based chiefly upon osteological characters. His nine orders are the following:

a. (extinct)—Ichthyosaurus.

b. (extinct)—Plesiosaurus, Pliosaurus, Nothosaurus, Placodus.

c. (extinct)—Dicynodon, Rhynchosaurus, Oudenodon.

d. .

e. (with the extinct Mosasaurus).

f. .

g. (with the extinct Teleosaurus and Streptospondylus).

h. (extinct)—Iguanodon, Scelidosaurus and Megalosaurus.

i. (extinct)—Dimorphodon, Rhamphorhynchus and Pterodactylus.

Owen was followed by Huxley and E. D. Cope, who, however, restricted still more the selection of classificatory characters by relying for the purposes of arrangement on a few parts of the