54 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 9 



Of 5 sexually mature males of albirostris which I have examined, 

 all had pouch flaps which did not meet in the midventral line, even though 

 the pouch contained no eggs (in an empty-pouched male of 95 mm. the 

 gape between the flaps was 1 mm. at its widest part and J^ mm. at its 

 narrowest part). A few eggs present in the pouch of one male averaged 

 ly2 mm. in diameter; they were distributed in a maximum of four rows 

 across the pouch and a single row in depth. Lateral protecting plates of 

 the pouch are very evident in the males of this species. 



When C. albirostris is compared with C. fasciatus (type of Bhanot- 

 ichthys), there are many similarities and also one marked difference. Of 

 specimens examined of this latter species, the eggs averaged one milli- 

 meter in diameter, and were arranged 4 to 6 in a row along the width of 

 the pouch and but a single egg in depth. The pouch flaps covered only 

 the outermost row of eggs of the brood. This is a great deal less coverage 

 than is found in albirostris. In fact, preserved males of fasciatus with 

 eggs in the brood pouch must be handled with extreme care, for the 

 clutch of eggs drops readily from the pouch. The reason for this is quickly 

 apparent, for in this species the pouch has no lateral protecting plates, 

 although they are well developed in albirostris. In cross section through 

 the brood pouch of fasciatus the ventral tail surface is flat, whereas in 

 albirostrisj because of the lateral protecting plates, it is inwardly concave. 

 Perhaps the most interesting fact about the developing embryos of 

 fasciatus is the orientation which they show. With very few exceptions 

 these oblong-shaped embryos have the eyespots turned toward the ventral 

 tail surface so that they do not show externally. No embryos of albirostris 

 were available for examination. 



As previously stated, two other characters have been cited as diag- 

 nostic for Bhanotichthys: the smooth head and the long, slender snout. 

 As to the first, Weber and de Beaufort (Indo- Australian Fishes, 1922, 

 4:71 ) were the first to point out that fasciatus has a w^ell-defined trilobed 

 occipital-nuchal crest. Even within the species, albirostris, the length of 

 the snout is an extremely variable character, for large individuals have 

 much elongated snouts. There then remains only one outstanding differ- 

 ence between Bhanotichthys and Corythoichthys, the absence or presence 

 of lateral protecting plates for the brood pouch. I do not hold this single 

 character to constitute a valid generic differentiation. Therefore, in my 

 opinion, Bhanotichthys should be regarded as a synonym of Corytho- 

 ichthys. 



