133 



Ennichthys megalops Girard^ Proc. Phil. Acad. N. S. vii. 



April, 1855, p. 323. 

 Ennichthys megalops Girard, P. R. R. Reports, vol. x. p. 



197, plate xxvii. and plate xxvi. fig. 10. 

 Bramopsis mento Agass., MSS. 



Hyperprosopon arcuatum Gibbons. 

 Syn. Hyperprosopon arcuatum Giblmis, Proc. Cal. Acad. N. S. 

 Daily Placer Times and Transcript, San Francisco, May 

 30, 1854. 

 Hyperprosopon arcuatus Gibbons, Proc. Phil. Acad. N. S. 



vir. July, 1854, p. 125. 

 Hyperprosopon argenteum Gibbons, Yar. A. H. punctatum, 

 Proc. Phil. Acad. N. S. vii. June, 1854, p. 106. 



Note. — Embiotoca Caiyi A(jass. does not belong to the genus Embiotoca. 

 An exammation of the skeleton of this species and of Embiotoca lateraHs 

 Agass., has convinced me that they must be separated from Embiotoca, and I 

 * would, therefore, propose for the first species the name of Hypsurus Caryi, 

 and for the second, the name of Tseniotoca laterahs. Girard had con-ectly 

 placed Gibbons' two species of Micrometrus in two distinct genera, Abeona 

 and Holconotus; but as Abeona is identical with the tj'pe of Gibbons' Micro- 

 metrus and the Holconotus of Girard is not the Holconotus of Agassiz as he 

 supposes, the species which Gibbons called M. aggregatus may be called 

 Metrogaster aggregatus Agass., retaining the generic name which Professor 

 Agassiz hnd given it on the drawings made at the time when he first received 

 these fishes from California. Besides the two species of Hyperprosopon de- 

 scribed by Gibbons, there is a third species, which has the general appearance 

 and about the size of IMetrogaster aggregatus Agass., but the teeth and the 

 shape of the dorsal show that it is a true Hyperprosopon, and I would propose 

 for it the name of Hyperprosopon analis. 



In speaking of the structural peculiarities of Holconoti, ]\Ir. Agassiz 

 remarked, that the part which contains the young is not the oviduct, 

 but the ovarian sheath, which fulfils the functions of the ovary. This 

 organ presents two modes of arrangement ; in one, there is a series of 

 triangular membranous flaps communicating with each other, between 

 which the fishes are arranged, mostly longitudinally, the head of one 

 to the tail of another, but sometimes with the bodies curved, to the 

 number of eighteen to twenty ; in the other, the cavity is divided by 

 three membranes converging to a point into four apartments, not 

 communicating with each other except toward the genital opening, the 

 young being arranged in the same longitudinal manner. From trac- 

 ing the egg from its very early stages, he was satisfied that this sheath 

 is the ovary and not the oviduct. He illustrated on the blackboard 

 the progressive development of the embryo, showing how the mouth 

 moved forward, the fins becoming distinct and rayed, and the dorsal 

 and anal at the time of hatching almost covering the caudal pos- 

 teriorly. 



