FOSSIL FISHES. St 
the appearance of a comb-like crest described by W. C. Redfield. This row 
of scales is, however, less strongly developed than in /schypterus tenuiceps, 
and the arch of the back does not show the hump which is so characteristic 
of that species; the fins are very strong; the fulcra of the dorsal and anal 
fins unusually broad and long, forming arches nearly half an inch wide at 
base, curving gracefully backward to a point; the anal fin when appressed 
reaches quite to the base of the caudal; the tail when expanded is three 
inches wide at its extremity; the scales of the sides are large and thick, | 
those near the head square or oblong. 
I have seen no such fishes as these anywhere except at Boonton. At 
Durham we find a species of Ischypterus of about the same size, but con- 
siderably broader—the mature form of Ischypterus micropterus N. At Sun- 
derland occurs another species (Z. Marshii) which in form and general aspect 
resembles those under consideration, but it is narrower, with less strong 
dorsal and anal fins, with thicker and relatively broader scales, which form 
more oblique rows on the sides. For these reasons I have thought it wise 
to regard it as distinct. 
IscHYPTERUS MICROPTERUS, Nl. Sp. 
Pl. IV, Figs. 1, 2; Pl. XU, Fig. 2. 
Fishes of medium or large size, five to ten inches long by one and a 
half to three and a half inches wide; form conical, greatest breadth at pec- 
toral fins, thence tapering uniformly to tail; back and abdomen about 
equally arched; head conical, acute, contained four and a half times in total 
length, nearly horizontal and straight below, rapidly sloped above; muzzle 
prolonged, acute ; mouth very small; maxillary and mandible slender, teeth 
small, conical, acute; cranial plates granulated ; operculum narrow; anterior 
margin vertical, posterior rounded, supraclavicles and clavicles slender; 
scales smooth, polished, oblong, twice as high as long on the sides near 
the head, rhomboidal on posterior portions of sides and tail; scales of ante- 
rior dorsal line about fifteen in number, rounded and emarginate at base, 
abruptly narrowed to smooth acute spines above; fins all relatively small 
and weak; anterior base of dorsal midway between tip of tail and extremity 
of muzzle; fulera eight, relatively small; fin rays eight, narrow, delicate; 
