912 THE AMERICAN NATURALIST. [Vor. XXXIX. 
Rata. 
The levator labialis superior in the skate has been differen- 
tiated into five parts (Figs. 3, 6, Zs 7-5). Of these the first 
(Lis 7) most nearly resembles the single muscle of Acanthias. 
It is small, cylindrical, and arises from the ventral surface of 
the cranium near the orbit and just behind the base of the eth- 
moid process. It runs laterally and then backward to the angle 
of the mouth, which it passes, to become inserted in the fascia 

Fic. 11.— 
Lateral view of Acanthias showing een and trapezius, Csd 1-6, con- 
res ist es dorsales; Csz za, or superioris ventralis, anterior fibers; 
Cre strictor superior is ventralis 2; /ntbr 1-4, 
interbranchiales ; Las, levator maxilla: 
sepeioris; Tr, trapez 
constri 

between the 
it separates. 
The second division (Fig. 6, 
labial muscles. 
adductores mandibularis medialis and lateralis which 
Lis 2) is much the largest of the 
It arises from the dorsal surface of the most 
lateral part of the ethmoid region in front of the antorbital proc- 
ess. The origin is small and of rather soft fibrous material. 
After passing dorsally of the large mass of the adductor man- 
