232 COPE. [Vol. VII. 



Pelvic arch. This consists of a simple slender costiform 

 bone, directed downwards and forwards from the diapophysis 

 of a single vertebra. It is homologous wholly or in part with 

 the ilium. 



ScINCIDjE. 



Dr. Boulenger remarks as to this family : " I have met with 

 great difficulty in arranging the genera of this family. The 

 majority of the characters hitherto employed for the distinction 

 of genera, such as the degree of development of the limbs, the 

 presence or absence of a transparent disk in the lower eyelid, 

 the presence or absence of keels or scales, etc., are in many 

 cases not even of specific value. I have therefore used certain 

 characters which hitherto have been neglected, but which, I am 

 convinced, afford a firmer basis for a natural arrangement. The 

 artificial nature of an arrangement based on the degree of the 

 development of the limbs has been pointed out by others. In 

 a family like the Scincoids, in which the limbs are undergoing 

 a process of abortion, this character must be abandoned as one 

 expressing relationship by itself. And I trust that the arrange- 

 ment of the species in one or more series within a genus, 

 passing from forms with well-developed pentadactyle limbs and 

 lacertiform physiognomy to such as have rudimentary limbs, or 

 even none at all, marks a great improvement upon the artificial 

 classifications in use down to the present day." 



I am not prepared to admit that the above remarks of Dr. 

 Boulenger have more than an application to the cases when the 

 development of the limbs and digits is irregular in the same 

 species. This has not been shown to be the case more fre- 

 quently than we expect to find in all other zoological characters, 

 and particularly in those which we call generic. It is, indeed, 

 precisely the grades of characters expressed by the last struc- 

 tural modifications of parts that the generic nomenclature is 

 created to record. So long as the characters are constant, then, 

 it is necessary to designate them by generic terms, and I have 

 therefore adopted in the following synopsis of genera those 

 which have been proposed by my predecessors for the various 

 degrees of development of the limbs and toes. In doing so, 

 however, I have adopted the primary divisions proposed by Dr. 

 Boulenger, as it is clear that they have a higher value than 

 those based on the number of digits, etc. 



