CATALOGUE OF SHLE1 D REPTILES. 



judge by the manner in whioh the specimens and tho 

 skulls of then are named in Museums, or Bent about by 

 the more scientific dealers, it would appear that ms yel 

 they are not properly understood. 



n.>t mean as to the precise limit of a speoies — -that 

 i say, whether tin' specimens from different districts of 

 the s.un. .1 or geographical province are mere local 



varieties of the same species or arc distinct; for that is a 

 question whioh 1 admit must, with the materials at our 

 command, for the present remain unsolved and open to dis- 

 -.'ii. lint it is not unusual to tind most distinct species 

 COnfnsed under the same name, and specimens of the same 



nly different in age, separated under two or more 

 nami s. 



1 have endeavoured to condense into a short synopsis the 

 principal leading characters, especially those furnished by 

 the examination of the skull and the nuchal and dorsal 

 plates, by which the different species of Crocodiles and 

 Alligators may be most easily determined, the object being 

 to furnish the zoologist with the best character to distin- 

 guish the different species of Crocodile and Alligator with- 

 out any pretence of giving an account of the comparative 

 anatomy or osteology of the species. I make this state- 

 ment, as confusion arises in the student's mind between 

 the object of the studies of the two branches of the science, 

 both equally important : but the one ought to be based on 

 the examination and comparison of the largest possible 

 number of specimens and species, while the most impor- 

 tant papers on comparative anatomy are often those which 

 arise from the examination of a single example of the 

 animal. 



There is a prejudice against such short essays ; and 

 they incur the reproach of certain continental and native 

 naturalists; but after considering their objection and their 

 practice. I am still of opinion that papers of the kind are 

 far more useful to the working naturalist than the long 

 descriptions of species which it is the custom of these natu- 

 ralists to prepare, when their descriptions, instead of merely 

 presenting the character of the species under consideration, 

 give in full detail under each species (so as to hide in a 

 mass of words the characters which you are looking for) 

 the character of the genus or even of the family or order 

 to which the species belongs. MacLeay well observes, " The 

 modern art of describing is too long, often insufferably long, 

 while human life remains as short as ever " (Illustr. Zool. 

 S. Africa, p. 54). 



I know by experience that synoptical papers take far 

 more mental and bodily labour to prepare than the descrip- 

 tion of a single specimen, often taken at haphazard and 



regarded as the type of a species because it presents some 

 striking peculiarities of appearanoe. 



This memoir, short as it is, is the result of the examina- 

 tion and repeated reexamination at different periods of 

 more than two hundred specimens of Crocodiles, — a series 

 of the most characteristic specimens of each species having 

 been laid out so that they could bo viewed and studied 

 together at leisure, and their peculiarities and likenesses 

 noted down. 



If all the notes made during these comparisons were 

 printed, as is the custom with many naturalists, they would 

 fill many pages, and thus make a large work. Many papers 

 and books are estimated by their size rather than by the 

 extent of labour that has been bestowed upon them ; while 

 the results of much labour and careful study, condensed 

 into a few pages, are often spoken of by critics, who never 

 undertook such researches, or who dislike the labour of con- 

 densing their observations into systematic order, as merely 

 the short notes of a hasty examination : at least that is the 

 way in which some papers, which were the results of 

 equally extensive examinations, have been regarded by 

 naturalists who should have known better. 



I may further observe that even after so much study, 

 when new specimens have been accumulated and with 

 additional experience, one finds peculiarities overlooked and 

 facts requiring verification when the old and newly ac- 

 quired specimens are submitted to a reexamination and 

 study. It is this experience that makes me inclined to 

 place less reliance than other naturalists upon essays pre- 

 pared by persons who come and look at a series of speci- 

 mens for the first time and describe them offhand. Yet 

 such works are often regarded as of authority, very often 

 on account of their length or the beautiful manner in which 

 they are printed or illustrated. 



The references to the ' Catalogue of the Osteological Spe- 

 cimens in the College of Surgeons ' are based on the exa- 

 mination of specimens in that collection ; and I have to 

 thank the Council of the College for their permission to 

 examine them, and Mr. Flower, the energetic Curator of 

 the collection, for his kindness and assistance in determining 

 them. 



If any evidence were required of the difficulties of de- 

 termining the species of this family, I need only refer to 

 the nomenclature of the skulls in the Catalogue above 

 referred to, which was prepared by the late Curator of the 

 collection, Professor Owen. 



In this collection, for example, I found what I consider 

 to be three distinct species in one case, and two distinct 

 species in another, confounded under the same name ; and, 



