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NOTES ON PHALLOSTETHID FISHES — MYERS 141 



Genus PLECTROSTETHUS Myers 



PLECTROSTETHUS PALAWANENSIS Mjers 



Plcctrostethus palawanensis Myers, 1935, p. 5 (mouth of the Caiholo River, 

 Ulugan Bay, west coast of Palawan). 



This slender little species has the most strongly rectilinear body 

 form of any phallostethid. That it has breeding habits similar to 

 Gulaph-allus and Phenacostethus is indicated by a grapelike cluster 

 of eggs that was still attached to the vent of one of the females when 

 I first examined them. These eggs are now U.S.N.M. no. 93424. 



CERATOSTETHUS, new genus 



Genotype. — Neostethus hicornis Regan. 



Outside of 'Phallostethiis, the fishes of this new genus are the 

 slenderest of all the phallostethids. The "neck" in particular is ex- 

 ceedingly slender. In this, and in their brackish-water habitat, they 

 differ strongly from the two known species of Gulaphallus. 



CERATOSTETHUS BICORNIS (Regan) 



Neostethus hicornis Regan, 1916, p. 14, fig. 11 (Kuala Laugat, Selangore). — 

 Myers, 1928, p. 9 (compiled). 



This form has been known hitherto only through the three imma- 

 ture type specimens in the British Museum. Besides eight adults 

 collected by Dr. A. W. Herre in brackish water in the northeastern 

 end of Singapore Island (U.S.N.M. no. 102142), the National Mu- 

 seum has six adults collected by the U. S. S. Albatross at Nakoda 

 Bay, on the west coast of the island of Palaw-an (U.S.N.M. nos. 98838 

 and 98839) and a single adult from the Malampaya River, Palawan 

 (U.S.N.M. no. 98840). 



There is little difference between the adult males and the subadult 

 figured by Regan (1916, p. 15, fig. lib), except in the more pendulous 

 IDOsterior end of the priapium, the better-developed oval pulvinulus, 

 the more pointed opercle, and the better development of the two 

 ctenactinia. The smaller ctenactinium is little longer than on 

 Regan's fish but more slender and curved. The longer ctenactinium 

 is curved upward, downward, and around the chin. There are two 

 rays in the first dorsal, and the second dorsal appears to have only 

 4 or 5 rays. Despite the fact that only one first dorsal ray has been 

 found in the types, I feel certain that these Singapore and Palawan 

 fishes are the same species. 



The anus of the female is surrounded by many folds of loose 

 tissue, this area being larger than in Neostethus lankestet-l. I do not, 

 however, find what I am certain is a homologue of the postanal 

 papilla of that species. The oviduct (and ureter?) appear to open 



