404 The American Naturalist. [May, 
As far as his argument applies to the Dipnoan pectoral Gill, 
may be safely followed, except in his view of the element abutting 
upon the occiput, which he regards as having intimate relations 
with the skull, and probably originating from it. In tracing 
back the homologies of the parts of the Dipnoan to those of the 
teleostome shoulder-girdle, Dr. Gill is less cogent, and the nom- 
enclature adopted by Gegenbaur ® appears preferable. The latter 
author figures the right half of the shoulder-girdle and the thor- 
acic fin of a teleostome fish (Gadus). Here there is no humerus 

Fic. 3.—Heptanchus griseus, left pectoral fin, pluribasal type. SB, ipit arch; 
N L, foramen; Pr, propterygium ; Ms, mesopterygium ; Mt, metapterygium ; a 4, exis of 
metapterygium; a, basilars; FS, fin-rays; from Wiedersheim. 
recognizable as such, but that the so-called “carpals” or basilars 
of the fin are regarded as representing it, is evident from the 
fact that the bone to which they are attached is styled the cora- 
coid, and that which abuts against it the scapula. The element 
corresponding to the “ proscapula” of Gill, and formed, accord- 
ing to him, of the united scapula and ectocoracoid, is by Gegen- 
baur called the clavicle, which is attached to the supraclavicle 
8 Elements of Comparative Anatomy, Second Edition, p. 475, 1877. 
