334 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



lack tentacles, my own experience indicates that even when these struc- 

 tures are fully developed they are often completely retracted and are 

 then all but invisible. 



The "hood" surmounting the sucker of Rhipidocotyle assumes various 

 forms. In R. baculum it is oval and kidney or bean shaped without pa- 

 pillae or corners; in several species it is pentagonal; or it may bear 

 papillae as in the type species, R. galeatum (Rud.). These papillae are 

 sometimes more or less extensible as in R. longleyi; they then suggest the 

 tentacles of Bucephalus, to which they are probably homologous. 



Eckmann (1932) lists Prosorhynchus squarnatus Odhner as a syno- 

 nym of P. crucibulus (Rud.) and redescribes what she considered this 

 species collected from Epinephelus sp. from the Suez. Nagaty (1937) 

 accepts this synonymy. Judging, however, from the detailed descriptions 

 of Odhner, 1905, and from specimens of Eckmann's material kindly sent 

 by Dr. Witenberg, the writer cannot agree with this conclusion and is 

 not satisfied that P. squarnatus is a synonym of P. crucibulus. Odhner 

 apparently studied type material of both species. P. squarnatus differs 

 from P. crucibulus primarily in its much weaker rhynchus not evidently 

 cone or wedge shaped, and in a linear rather than a triangular arrange- 

 ment of gonads. The latter character may vaiy somewhat (according to 

 Nicoll, 1910). P. crucibulus tends to be more elongate. The egg of each 

 species is without a polar process. 



The Suez material referred by Eckmann to P. crucibulus has such 

 distinctive eggs with very conspicuous polar processes that it seems to 

 represent a new species altogether. The writer has never observed such 

 processes in any species of Prosorhynchus, and they almost certainly could 

 not have been overlooked by Odhner and others in P. crucibulus. The 

 name Prosorhynchus caudovatus n. nom. is here proposed for the Pro- 

 sorhynchus crucibulus of Eckmann. This name indicates the taillike 

 process on the egg, the distinguishing character of the species. 



Nagaty (1937) apparently re-establishes the validity of Alicornis 

 MacCallum. Several other genera of gasterostomes have very uncertain 

 status. Gotonius is generally considered to be a synonym of Prosorhyn- 

 chus. The writer agrees with Nagaty in the following : Prosorhynchoides 

 Dollfus, 1929 a synonym of Bucephalopsis ; Skrjabiniella Issaitschikow, 

 1928 a synonym of Prosorhynchus. Shen (1930) named P. vaneyi, a 

 species peculiar in possessing a triple crown of spines around the "ros- 

 trum" or rhynchus. Eckmann (1932) placed P. vaneyi in the genus 

 Dollfusina, which name being preoccupied was changed (by Eckmann, 



