66 Cr. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



LeptocoUus. From tlie former it differs by the presence of teeth on the palatine hones and the 

 ahsence of maxillary barbels ; from the latter by the continuity of the gill openings, the inser- 

 tion of the ventrals ; and, finally, from both, as well as from all the genera of this family, by 

 the structure of the anal fin, the three anterior rays of which are stouter, more developed, and 

 somewhat isolated from the rest, especially in the male sex. 



1. OLIGOCOTTUS MACULOSDS, Grd. 



Spec. Char. — Head sub-conical. Mouth moderately cleft ; postericr extremity of maxillary extending to a vertical line 

 intersecting the pupil. A stouiish bicuspid process on the convexity of the preopercle. Two acute nasal spines. Dorsal fins 

 contiguous. Origin of anal in advance of the anterior margin of second dorsal. Yellowish brown above, mottled or variegated 

 with blacltish ; along llie dorsal region a series of blotches of a deeper hue ; lower half of sides vermiculated. Abdomen of 

 a bright saflron hue in the male. Inferior surface of liead with traces of black markings ; tliroat and abdomen unicolor, as also 

 the ventrals and anal. Dorsals, caudals, and pectorals transversely barred. 



Sta.—Oligocoltus maculosus, Grd. Pro. Acad. Nat. Sc. Philad. VIII, 1856, 133 ; &., Journ. Bost. Soc. Nat. Hist. VI, 1857. 



Plate xxiv, Fig. 7. 



Among all the specimens which we have examined, none attained an absolute size of three 

 inches ; and what gives us to think that we deal with adult individuals is the fact that the 

 females are full of ripe spawn, and both sexes clothed with the brilliant hue peculiar to that 

 eventful period in ichthyic life. 



The head is but very slightly broader than deep ; its upper surface is depressed and smooth, 

 the interocular space grooved, the snout very declivous, and consequently short, narrow, and 

 rounded upon its periphery. The upper jaw protrudes slightly beyond the lower one ; the 

 mouth is small, being but moderately cleft ; the posterior extremity of the maxillaries extending 

 to a vertical line intersecting the pupil. The eye is sub-circular, and its diameter contained 

 four times in the length of the side of the head, exactly once in advance of its anterior rim. 

 The head itself forms a little less than the fourth of the entire length. A rather stout bicuspid 

 process arises from the convexity of the preopercle with its acute spines directed obliquely 

 upwards. No other spines are apparent upon the opercular apparatus. We omitted, in speaking 

 of the upper surface of the head, to mention two prominent and acute nasal spines ; the nostrils 

 being, as usual, placed one behind, and the other beneath, each spine. The branchial apertures 

 are continuous under the throat, and the branchiostegal rays six in number. 



The body is very much compressed, sub-fusiform, and deeper than broad even anteriorly. The 

 anterior dorsal is lower than the posterior one, and contiguous to the latter near its base ; its 

 orit^in is situated in advance of the base of the pectorals, and consequently close to the occiput. 

 It is composed of eight slender spines nearly equal in height, giving the outline of the fin the 

 appearance of a depressed curve. Its base is somewhat more than the half of that of the second 

 dorsal. The latter is composed of sixteen or seventeen slender and undivided rays, diminishing 

 slightly in height from the second backwards, the first ray being a little shorter than the 

 second. The extremities of the posterior rays do not quite reach the base of the caudal. The 

 caudal fin is slender and proportionally well developed ; it constitutes a little less than the 

 fifth of tlie total length, being comprised three times on the space between its base and the 

 thoracic belt. The origin of the anal fin is situated a little in advance of the anterior ray of 

 the second dorsal, composed of thirteen undivided rays, the three anterior of which being deeper 

 and stouter than the rest, particularly in the male, where they project beyond the general 

 outline of the fin. The interradial membrane is deeply emarginated. The extremities of the 

 posterior rays do not extend so far back as those of the dorsal opposite. The ventrals are 



