REPTILIA. 321 



Mabuya dominicana Garman. 

 Garman, Bull. Essex inst., 1SS7, 19, p. 52. 



"Mr. Garman describes specimens from Dominica as a distinct species, 

 said to be distinguished from M. agilis by having the supranasals separate from 

 each other, and possessing from 68 to 72 scales in a series between the chin and 

 vent. His M. agilis is stated to have the supranasals in contact with each other 

 and only 54 or 56 scales between chin and vent. 



The eight adult specimens from Dominica before me vary in both these 

 respects; some have the supranasals in contact, others not. Between chin and 

 vent there are 60 scales in two, 62 in one, 63 in two, and 64, 65, and 67 severally 

 in single specimens. Therefore the characters on which Mr. Garman based his 

 distinction are in these specimens so obviously variable that no herpetologist 

 will place any reliance upon them. 



But to prove the variability of these characters in this species beyond further 

 dispute I took from a gravid female six embryos, all fully developed and about 

 half the length of the mother. The mother had the supranasals in contact with 

 each other and 62 scales between chin and vent. Of her progeny two had 

 the supranasals as in the mother, in three they were separate from each other, 

 whilst one might be assigned to either category. The scales on the abdomen 

 are in 57 rows in two of these embryos and in 61, 62, 65, and 66 rows severally 

 in their brothers. 



Specific distinctions in these days are held to be, and often may be, matters 

 of individual opinion and, as a rule, I abstain from entering into any discussion 

 about them; but they sometimes have a direct bearing upon wider and more 

 important questions. In this case any one studying the distribution of reptiles 

 over the West Indies would, by relying on statements such as are propounded 

 by Mr. Garman in his recent publications on West-Indian reptiles, be misled 

 into the view of a more complete isolation and specialization of the faunas of 

 the various islands than obtains in reality. He states in fact in this instance 

 that the widely distributed Mahuia agilis has been sufficiently differentiated in 

 Dominica to form a distinct species or whatever it may be called, whilst the 

 examination of even a small number of examples disproves this statement. 

 Distinctive characters, no matter how trivial they appear to be, become impor- 

 tant enough to the systematic zoologist if they be found constant in a number of 

 specimens and correlated to some other point of the life of an animal; but unless 

 this has been ascertained to be the fact, their indiscriminate use impedes rather 

 than advances zoology." 



