GREGORY: FISH SKULLS 



401 



(6) although the mandible is delicate, the palato-quadrate arch is unusually massive, 

 apparently a secondary enlargement to support the massive neurocranium which rests 

 upon it; 



(7) while in Antennarius and Lophius the opercular is exceptionally small, in Ogco- 

 cephalus vespertilio it has enjoyed a secondary enlargement, so that it has grown backward, 

 retaining its contacts with the still more enlarged subopercular. 



The skeleton of Chaunax coloratus as figured by Garman (1899, Pis. XVI, XVII) 

 would seem to afford an ideal intermediate stage leading to the sea-bats from a primitive 

 Antennarius-Vike type. The illicium (Fig. 271) is received into a fossa in the ethmoid region. 



pnif. 



Fig. 273. Cryptojparas. Sketch of very young specimen from stained preparation by Miss Gloria Hollister for 



Dr. William Beebe. 



the opercular and subopercular are enlarged and foreshadow the relations of these elements 

 in the sea-bats; but the mouth is less reduced in size and the skeleton abounds in deep-seated 

 resemblances to the antennariids. Hence it is not surprising that Tate Regan (1912/, p. 

 283) puts the Chaunacidae between the Antennariidae and the Onchocephalidae and in the 

 division Antennariiformes. 



The Ceratioids. — The oceanic anglers ordinarily live at depths from about 500 to 1500 

 metres below the surface (Tate Regan, 1926). Accordingly they are usually black but 

 occasionally have a pale translucent skin. The body is typically short, more or less globose, 

 with a great upturned mouth bristling with long sharp teeth. The stomach, as in other 

 pediculates, is distensible. The illicium usually bears a glowing bulb at the tip, but it may 

 be vestigial or specialized in various ways. The eyes are typically small and are doubtless 

 directed toward the prey in front of the illicium. The small backwardly directed, soft 

 dorsal fin usually lies well behind the swollen abdomen and is frequently paired with the 

 small anal. The caudal peduncle is usually wide and the tail has more or less webbed rays 

 and is convex posteriorly. Probably the fish moves up quietly toward its prey by the 

 undulations of these three fins. The pectorals are small but retain their pediculate type 

 and are often directed upward and backward. The ventral fins are absent, but Parr (1930, 

 pp. 11, 13) reports the presence of pelvic bones in Rhynchoceratias longipinnis. 



