LITEKATURE.] REPTILES 439 V.s on ' 18 commensurate with the amount of labour bestowed on its compilation. 6. Special Systematic Works. After having followed the general history of herpetology to the present period, we have to mention the works by which our knowledge of certain orders or of the various Eeptilian faunae has been specially advanced. Crocodilia and Lacertilia. We have already shown that the animals of these two orders were by the earlier authors thrown together in one group, of which a natural subdivi- sion into families was attempted by Oppel and Cuvier, that Merrem (1820) was the first to recognize in the Cro- codiles a separate group for which he proposed the name of Loricata, being followed therein by Blainville, who named the group Emydo-sauriens, and that Latreille actually recog- nized their affinities to the Chelonians, uniting them under the name of Cataphracta. In Wagler's and Fitzinger's systems a distinct advance is manifested by the employ- ment of the tongue and also of the dentition as important characters. These, combined with the scutellation, the form of the toes, and the entire habitus, were also the characters on which the subsequent classifications by Wiegmann, Dumdril and Bibron, Gray, and Stannius were based, the classifications varying according to the manner in which those characters are subordinated to one another. But, while the German and English herpetologists assign to the Amphisbaenians, Chamaeleons, and Crocodiles a rank more or less above, and distant from, the Lacertilian families, Dumeril and Bibron take a singularly retrograde step in dividing Lizards into eight equivalent families, of which the first comprises the Crocodiles, and the second the Chamte- leons, the Amphisbsenians forming part of the family Chalcididse. Gray was the last who dared to place the narrow-mouthed Snakes such as Typhlops and Rhinophis among Lizards. In the two most recent classifications of the families of Lizards osteological (or rather craniological) characters supersede almost entirely those previously employed. COPE, 1 who had led the way in this direction, still allows subordinal value to the dentition as well as to the form of the tongue, as may be seen from the following scheme : Suborder 1. HHIPTOGLOSSA. Fain. 1. Cham&leontidae. Suborder 2. PACHYGLOSSA. Fam. 2. Agamidse. Suborder 3. NYCTISAURA. Fam. 3. Gecconidie. Suborder 4. PLEURODONTA. a. Iguania. Fam. 4, Anolidx; 5, lyuanidx. b. Diploglossa. Fam. 6, Anguidas ; 7, Gerrhonolidas ; 8, Xcnosauridse ; 9, Helodermidas. c. Thecaglossa. Fam. 10. Voranidae. d. Leptoglossa. Fam. 11, Teiidse; 12, Lacertidx; 13, Zonuridse; 14, CJuil- cididse; 15, Scincidie; 16, Sepsidas. e. Typhlophthalmi. Fam. 17, Anelytropidae ; 18, Acontiidse ; 19, Aniellidx. Suborder 5. OPHIOSAURI. Fain. 20, Amphisbaenidas ; 21, Trogonophidx. Finally, whilst adopting in principle Cope's classification, G. A. BouLENGER, 2 partly by extending his examination on types not seen by Cope, partly by differently valuing the various craniological characters, introduced considerable modifications : 1 Proc. Acad. Nat. Sci. Philadelphia, 1864, pp. 224 s?., and Proc. Amer. Assoc. far the Advancement of Science, 1870 (1871), pp. 236 sq. 8 For an outline of his classification consult Ann. and Mag. 2fat. Hist., Aug. 1884, or Catalogue of Lizards, vol. i., 1885, p. 1. Suborder 1. LACERTILIA VERA. A. Tongue smooth or with villose papillae ; clavicle dilated, loop-shaped proximally ; no postorbital or postfrouto- squamosal arches. Fam. 1, Geckonidae. ; 2, Eublepharidae. B. Tongue smooth or with villose papillae ; clavicle not dilated proximally. Fam. 3,' Uroplatidae ; 4, Pygopodidas ; 5, Agamidse, ; 6, Iguanidae ; 7, Xenosauridse ; 8, Zonuridse ; 9, Anguidx ; 10, Aniellidas ; 11, Helodermatidae ; 12, Varanidas. C. Tongue covered with imbricate, scale-like papilla or with oblique plicae ; clavicle dilated proximally, frequently loop-shaped. Fam. 13, Xantusiidx ; 14, Tciidae; 15, Amphisbaenidae ; 16, Lacertidaz; 17, Gerrhosauridaz ; 18, Seineidae ; 19, AnelylropidiK ; 20, Dibamidae. Suborder 2. RHIPTOGLOSSA. Fam. 21. Chamzeleontidae. The principal works to be consulted by the student of recent Crocodilians are the following : Cuvier, Ossemcns fossiles, vol. v. part 2 (1824) ; Geoffroy St Hilaire, "Descriptions des Crocodiles du Nil," in Mem. del'Institut d'Egypte (1813) ; Dumeril and Bibron, Erpttologie ge'ne'rale, Paris, 8vo, vols. ii. , iii. (1835-36) ; Huxley, " On the dermal armour of Jacare and Caiman, with notes on the generic and specific characters of recent Crocodilia," in Jour. Proc. Linn. Soc., Zoology, vol. iv. pp. 1-28 (1860) ; Briihl, Das Skclett der Krokodiliner, dargestellt in 20 Tafeln (1862) ; Strauch, "Synopsis der gegenwartig lebenden Crocodiliden," in Mem. Acad. St Petersburg, vol. x. (1866) ; Rathke, Untcrsuchungcn uber die Entwickelung und den Korperbau der Crocodile, Brunswick, 4to (1866) ; Gray, Catalogue of Shield- Reptiles in the Collection of the British Museum, part ii., Eniydo- saurians, Pihynchocephalia, and Amphisbaenians, London, 4to (1872) ; Parker, On the Structure and Development of the Skull in the Crocodiles, London, 4to (1883). The principal special works to be consulted by the student of recent Lacertilians are the following : Wiegmann, Herpetologia mexicana, Pars 1, Saurorum species am]}lectens, Berlin, fol. (1834) ; Dumeril and Bibron, Erpelologie generate, Paris, 8vo, vols. 2-5 (1836-39) ; Gray, Catalogue of the Specimens of Lizards in the Collection of the British Museum,, London, 16rno (1845) ; Briicke, Bcitrdge zur vcrgleichenden Ana- tomic und Physiologic des Gcf ass- Systems der Amphibien, Vienna, 4to (1852) ; Kathke, Uebcr den Bau und die Entwicklung des Brustbeins der Sauricr (1854) ; Fritsch, Zur vergleichenden Ana- tomie des Amphibien-Iferzcns, Berlin, 8vo (1869); Fiirbringer, Die Knochcn und Muskeln der Extremitdten bei den schlangcndhitlichen Sauricrn, Leipsic, 4to (1870) ; Braun, Das Urogenitalsystcm der cinheimiscJien Reptilien, Wiirzburg, 8vo (1877) ; Parker, On the Structure and Development of the Skull in the Lacertilia, (1879) ; Boulenger, Catalogue of the Lizards in the British Museum, 2d edition, London, 8vo (vol. i. in progress, 1885). In a short sketch like the present it would be impossible to refer even to a small part only of the immense number of contributions by which our knowledge of Lizards has been advanced within the last forty years, either by adding to that of species previously imperfectly known, or by de- scribing new generic and specific forms. But an idea of this increase may be formed by a comparison of Gray's and Boulenger's catalogues ; whilst the former enumerated 186 species out of the families Geckonidse. and Agamidse, Boulenger describes not less than 490 belonging to the same groups. Ophidia. We have already mentioned that in Oppel's on OpLi- system (1811) the first step is taken towards a natural diarw ; classification of Snakes. Neither C. Dumeril nor Merrem, Fitzinger nor Wagler, indicated the way towards a more natural arrangement ; it seemed almost as if with the increase of the number of distinct genera their arrange- ment became more and more hopeless. In the meantime the Rijks Museum of Leyden had enriched itself under the able direction of Temminck, through the efforts of traveller- naturalists like Eeinwardt, Kuhl, Van Hasselt, Boie, and Siebold from the Dutch colonies in the East and West Indies, with materials fairly rivalling those accumulated in Paris. They were at first studied by the brothers Friederich Boie and Heinrich Boie, who well characterized
