260 
BULLETIN OF THE BUBEAU OF FISHERIES 
9. Priapichthys fosteri sp. nov. 
Chimbola 
Type No. 87263, U.S.N.M.; male, length 38 mm., Rio Lempa, San Marcos. 
Head, 2.95 to 5.2; depth, 3.25 to 4.8; D., 8; A., 9 or 10; scales, 27 to 30. 
Body moderately compressed anteriorly; caudal peduncle deep and strongly 
compressed, 1.4 to 1.8 in head; profile straight from snout to nape, gently convex 
from nape to dorsal; head broad, flat above; snout short, broad, 3.2 to 4.25 in 
head; eye, 2.7 to 3.7; interorbital, 1.85 to 2.9; mouth small, the cleft transverse; 
teeth loosely attached, the outer series slightly broadened, curved inward, and 
well separated from the very minute inner teeth; scales cycloid, present on head 
and snout and on base of caudal, each scale with 6 to 11 radii; average of 30 scales 
taken from 10 specimens, ranging from 23 to 61 millimeters in length, 8.86 + ; 
origin of dorsal in female a little in advance of middle of anal, occasionally equi- 
distant from the tip of snout and the end of caudal, but more usually an eye's 
diameter nearer the latter; dorsal placed further forward in adult male, about 
an eye's diameter nearer tip of snout than end of caudal; caudal fin broadly 
rounded; anal fin in females and young similar to the dorsal, its origin about equi- 
distant from tip of snout and base of caudal; anal fin in adult males inserted far 
in advance of dorsal, greatly produced, much longer than head, failing to reach 
base of caudal by a distance equal to the length of snout and eye, the third, fourth, 
and fifth rays all of abouti equal lengtli, the branches greatly crowded distally 
and forming a compound curve, the apex being directed forward, the posterior 
branch of the median produced ray bekring about 16 spurlike hooks on its pos- 
terior margin: ventral fins reaching origin of anal in young, scarcely to vent in 
adult females, past the origin of anal in males; pectoral fins moderate, 1 to 1.35 
in head; vertebrae 15 + 17; alimentary canal scarcely as long as body; peritoneum 
black. 
Color of the sexes similar; upper parts greenish; lower parts silvery; sides 
with from 6 to 10 dark crossbars; a narrow vertebral line; a sharp dark median 
line from anal to caudal; ventral fins yellowish; other fins all slightly olivaceous. 
This species is represented by 98 specimens, ranging from 35 to 80 millimeters 
in length. It was taken only in the Rio Lempa at San Marcos and at Suchitoto 
in quiet water, and 2 specimens were secured in brackish water in the estuary at 
El Triunfo. The males in this species, as is usual for the family, are much smaller 
than the females and fewer in number. 
Many of the specimens collected (during January and February) were in 
spawning condition. Embryos and eggs of several sizes usually were present in 
one ovary. The ovary from a female 80 millimeters long, for example, contained 
44 well-developed embryos, 42 "eyed" eggs, and 44 large, probably mature, eggs. 
Two other ovaries contained, respectively, 7 large embryos and 20 eggs in the 
"eyed" stage in addition to smaller ova. 
The stomachs examined contained principally fragments of insects and vege- 
table debris. The species is quite probably of value as an eradicator of mosquito 
larvfe. 
