394 CALIFORNIA ACADEMY OF SCIENCES. 22 
but is distinguished by the more declivous forehead and 
the shape of the rostro-frontal fontanelle. 
‘*A single specimen was forwarded to the Smithsonian 
Institution by S. E. Hubbard, Esq., of San Francisco, 
Cal?” (Gill) 
21. Manta birostris (Walbaum). 
Said to be frequently seen in the open sea about Ma- 
zatlan; not obtained by us. 
Family SILURID/E. 
22. Felichthys pinnimaculatus (Steindachner). 
Occasionally taken in the estuary. Recorded by Gil- 
bert from Mazatlan and Panama, by Steindachner from 
Altata, Costa Rica and Panama. ‘Two specimens ob- 
tained by us. 
23. Felichthys panamensis (Gill). 
Not rare in the estuary, reaching a considerable size. 
Obtained by Gilbert at Mazatlan, Libertad, Punta Arenas; 
by Gill and Giinther at Panama; and by Steindachner at 
Magdalena Bay, Altata and Panama. One specimen ob- 
tained by us. 
24. Galeichthys peruvianus Liitken. PANAmMa. 
Recorded by Steindachner from Altata; not seen by 
us, and taken by Dr. Gilbert only at Panama; apparently 
not common. . 
The so-called genus Ga/e7chthys is distinguished trom 
Hexanematichthys only by having the bones of the head 
covered by skin. In several species of other genera 
(notably platypogon, dasycephalus, gilberti), the skin on 
the head is thickened in females, obscuring the outline 
and granulation of many of the bones. It may be that 
the species called Galezchthys represent only the extreme 
