CHONDROCRANIUM OF EUMECES 133 
hypoglossal canal in adult skulls” Lillie was ‘‘unable to decide 
whether there were three or four hypoglossal canals develop- 
mentally”? (p. 144). Conditions in embryonic Eumeces seem 
hardly more decisive than in adult Homo. 
J. G. Fischer (52) is cited by Gaupp (08 a) as affirming the 
absence of hypoglossus foramina in Varanus, Crocodilus bipor- 
eatus, Crocodilus acutus, and Alligator punctulatus, the hypo- 
glossus roots leaving the skull in company with the vagus through 
the fissura metotica; in Istiurus an anterior root has a similar 
exit, although the posterior root is provided with an independent 
foramen. A careful examination of Fischer’s paper, rather ob- 
scure in this connection, leaves me unconvinced of the accuracy 
of this citation except as regards the anterior root in Istiurus 
and Varanus. Concerning these Fischer’s statement is explicit. 
This record, unique for the Reptilia, must be accepted with cau- 
tion until confirmed on the basis of modern technical methods; 
on the other hand, it is of more than passing interest, because 
of the fact that an identical arrangement has been long recognized 
in adults of Echidna and Ornithorhynchus, and has been demon- 
strated by Gaupp (08 a) in all embryonic stages of the former. 
Gaupp holds this as confined to the monotremes alone, at least 
among mammals—‘‘eine Besonderheit der Monotremen;”’ but 
de Burlet (14 a, ’16) has described the same course of the hypo- 
glossus in an embryo of Balaenoptera and in adult skulls of a 
number of other Cetacea and Sirenia. It should be noted that 
a separate foramen was found in other skulls of some of these 
species, and that some specimens (among them the Balaenoptera 
embryo) showed the exit through the fissura metotica on one side 
only. Owing to the scarcity of the material, it is impossible to 
determine which is the normal structure and which the excep- 
tional in these orders. 
Nerve VI. The foramen for the abducens nerve (fig. 1, 
f.n.VI.) is located exactly as in Lacerta and, apparently, all other 
reptiles. The nerves pass through a pair of tunnels excavated 
in the thickened cartilage of the crista sellaris near its lateral 
limits and located each immediately above the common origin 
of the corresponding trabecula (trab.) and basipterygoid process 
