256 
BULLETIN OF THE BUREAU OF FISHERIES 
inward, and well separated from the inner, minute, villiforjn ones; scales cycloid, 
enlarged ones present on head and snout, 11 or 12 in median series from occiput to 
dorsal, 8 complete longitudinal rows between dorsal and anal; dorsal fin with con- 
vex margin, occasionally nearly straight, the origin in females and young a little 
in advance of the anal and a little nearer the base of caudal than posterior margin 
of eye; dorsal much higher in the adult male and situated slightly farther forward, 
quite as near the eye as the base of caudal; caudal fin strongly convex' to nearly 
straight; anal fin small, its origin in female slightly nearer base of caudal than eye, 
farther forward in adult males, usually an eye's diameter nearer tip of snout than 
base of caudal, and modified into a copulatory organ, but not greatly produced, 
always shorter than head, the produced portion anteriorly with a sort of membra- 
nous hood, which is free distally, the third, fourth, and fifth rays produced, 2 
branches each of the anterior and median produced rays reaching the end of the 
organ, the branches of the anterior ray with small antrorse hooks at tip, the pos- 
terior branch of the median produced ray with 8 or 9 prominent spurlike hooks 
below the apex of the organ, the posterior produced ray not quite reaching the 
apex, both branches coterjninal, each bearing a small posterior hook; ventral fins 
in the female moderate, inserted about equidistant from margin of opercle and end 
of anal base, reaching vent in large examples, to origin of anal in small ones, the 
third ray somewhat produced in the jnale and reaching beyond the base of fin; 
pectoral fins moderate, 1 to 1 .8 in liead. 
Color variable, fresh females 54 millimeters long, dark olivaceous above; lower 
part of sides silvery with bluish reflections; prJe underneath; scales on sides with 
indications of rusty spots; dorsal red with black spots near base; caudal greenish 
with faint elongate dark spots; anal and ventrals plain; pectorals slightly greenish. 
Color of male, 37 millimeters long, identical except for more red and larger and 
more pronounced black spots on dorsal fin. Some specimens plain without spots; 
others with prominent dark spots along the rows of scales on median part of sides; 
still others with pronounced brick-red spots (pale in spirits) along the rows of 
scales on sides; an occasional specimen with irregular dark blotches on sides; 
many specimens with plain to faint pale crossbars; a dark caudal spot frequently 
present; dorsal fin usually spotted v/ith black, the spots varying in number, size, 
and intensity; caudal fin frequently plain but oftener with elongate dark spots. 
Many specimens of this species, ranging from 10 to 120 millimeters in length, 
were preserved. It is the most abundant and the most universally distributed of 
all the fishes of the Republic. It was taken in every locality except in the Rio 
Molino, in wdiich collections were made in fresh water. It was found in lakes, 
swamps, and streams, and it does not shun currents to the extent that most top 
minnows do, but it evidently finds the environment of the quieter waters more 
congenial, as it is found there in greatest abundance. This fish occurs mainly in 
shallow water, but it is also found along the shores in water several feet deep. It 
is abundant among vegetation and frequently, also, along rocky shores. This 
species was found to be especially abundant in Lakes Chanmico, Chalchuapa, and 
Coatepeque. In Lake Guija it was common along the shores but less numerous 
than its smaller, spotted relative, Priapiclithys letonai. In Lake Olomega M. 
sphenops was less abundant than in any other lake visited, notwithstanding that 
