FISHERY BULLETIN: VOL. 71. NO. 3 



•«M^ 



B 



Figure 7. — Juvenile stages of A) Etropus microstomus (41 mm SL) and B) Cilharichthys arctifrons 



(40 mm SL). 



ally compressed. The caudal region is slender. 

 At comparable sizes, larvae of E. microstomus 

 are deeper-bodied than those of C. arctifrons 

 immediately posterior to the anus. With in- 

 creasing age, the head and peritoneal cavity 

 occupy proportionately less of the body length. 

 The dorsal body outline becomes convex. As 

 metamorphosis approaches, the body deepens, 

 and the ventral body outline becomes convex. 

 The adult shape, in which the greatest body 

 depth occurs behind rather than at the anus, 

 is approached. 



The fore-, mid-, and hindbrain are distinctly 

 outlined in 2.5-mm larvae of both species and 



remain so until metamorphosis. A nasal capsule 

 is evident on the snout at about 3 mm in both 

 species and remains prominent until metamor- 

 phosis. The left otolith becomes noticeable in 

 the head on the eyed side of E. microstomus at 

 about 10-11 mm. It is not observable in C. 

 arctifrons. 



The coils of the alimentary tract can be seen 

 clearly in 2.5-mm larvae of both species with 

 the hindgut ending in a nearly vertical position 

 immediately posterior to the main visceral 

 mass. As the larval development proceeds, the 

 position of the anus shifts anteriorly until it 

 rests adjacent to the base of the left pelvic fin 



748 



