158 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Fig, 82. Eggs of argentinoids. (A) Argentina sialus. 1.5 mm, CalCOFI 5103, Sta. 1 17.35; (B) Microstoma sp., 2.2 mm, CalCOFI 751 1, Sta. 

 87.90; (C) Nansenia Candida. 1.4 mm, CalCOFI Sta. 60.90; (D) N. crassa. 1.5 mm, CalCOFI; (E) Bathylagus stilhius. 1.1 mm, from Ahlstrom 

 (1969); (F) B. schmidli. 1.8 mm. from Ahlstrom (1969); (G) B. ochotensis. 1.1 mm, CalCOFI 5002 Sta. 60.90; (H) B. weselhi. 1.0 mm, Ahlstrom 

 (1969); (I) B. nigrigenys. 0.96 mm. CalCOFI 5106 Sta. 157.20. 



the post-pyloric bulb. In Macropinna and Opisthoproctus there 

 is a straight section leading posteriorly from the pylorus, which 

 ends in an S-shaped fold and an enlarged rectal bulb, the latter 

 described by Bertelsen and Munk (1964). The anterior section 

 including the sac and pyloiojs have longitudinal internal ridges 

 while sections posterior to this have transverse rugae. In late 

 larval stages the entire section posterior to the pylorus becomes 

 part of the S-shaped coil. 



The head is relatively small in argentinids and has a rounded 

 blunted anterior profile (Fig. 83, Table 40). It is slightly larger 



in most microstomatids, with the exception oi Microstoma sp. 

 (Pacific form) which has a small head. In most microstomatids 

 the head has a rounded, blunted anterior profile and is bent 

 slightly downward from the longitudinal axis. In both families 

 the eye is either round or slightly ellipsoidal. In bathylagids the 

 head is moderate in size but highly various in shape (Figs. 85, 

 86; Table 40). The snout is generally longer than in Argentinidae 

 and Microstomatidae. 



Eye shape and structure vary greatly within the bathylagids. 

 Bathylagus milleri has a large, nearly round eye in contrast to 



