NATURAL SCIENCES OF PHILADELPHIA. 123 



Elcotris dormitatrix Cuv., Regne Animal, vol. ii. 



Eleotris dormitatrix Guerin, Iconographie du Regne Animal. 



Philypnus dormitator Val., Hist. Nat. des Poissons, vol. xii. p. 255. 



Philypnus dormitator Storer, Synopsis Fishes of North America, ib. in Me- 

 moirs of American Acad., vol. ii. 



Philypnus dormitator Girard, United States and Mexican Boundary Survey, 

 Icthyology, p. 29, pi. xii. fig. 13. 



This species has been very fully described by Valenciennes. He had ex- 

 amined specimens from Porto Rico, St. Domingo and Martinique. It has also 

 been found at Mexico. 



Dr. Girard has given a figure of a very small species of this genus under the 

 name of Philypnus dormitator. It is very probable the young of that 

 species, but as the only specimen in the Museum is one of fifteen inches in 

 length, obtained by the author at the junction of the Arouca and Caroni rivers, 

 in the island of Trinidad, there is no means of comparison. The specimen 

 described by Dr. Girard has very large eyes, and other characters of an ex- 

 tremely young fish. It was obtained at the mouth of the Rio Grande by Mr. 

 John H. Clarke, the Naturalist of the " United States and Mexican Boundary 

 Survey," and is preserved in the Smithsonian Museum. 



Philypnus lateralis Gill. 



In general outline of form, this species has considerable resemblance to the 

 Philypnus dormitator. The dorsal outline ascends in almost a straight 

 line from the snout to the front of the dorsal fin, the chief variation existing 

 between the eyes, where there is a slight depression. The back under the 

 first dorsal is straight ; at the second, it declines very little and in almost a 

 straight line to the base of the caudal fin. The abdominal outline from the 

 ventrals to the caudal fin converges in nearly the same proportion as the dor- 

 sal. The greatest height of the body, at the first dorsal ray, is equal to about 

 one-fifth of the total length, inclusive of the head and caudal fin ; the least 

 height at the base of the caudal is half of the greatest. 



The head, in profile, is conical or elongated triangular ; it forms three-tenths 

 of the total length. Its dorsal and inferior surfaces regularly converge towards 

 the tip of the lower jaw, and the declension of the former is about twice as 

 great as the ascension of the latter. The dorsal surface over the operculum 

 is rounded, and the degree of convexity becomes less towards the eyes, be- 

 tween which it is flat. The breadth at the operculum equals about half the 

 length of the head, and under the eyes it is between one-fourth and one-fifth 

 less. The interocular space is somewhat less than half of the breadth at the 

 opercula. The outlines of the jaws are semi-elliptical. 



The eyes are longitudinally oval, and are at the third sixth of the head's 

 length. 



The preoperculum in its declination recedes considerably backwards, and 

 is thence broadly curved forwards. The distance from the orbit to the pre- 

 opercular angle, equals the distance from the posterior border of the orbit to 

 its horizon behind the intermaxillaries. The operculum declines obliquely 

 downwards from its membranous point, and its greatest length, in an oblique 

 direction, slightly surpasses the interval between the orbit and the angle of 

 the preoperculum. The oculo-humeral groove is shallow and scarcely ascend- 

 ing. 



The mouth is oblique and large, the maxillaries extending backwards to 

 the vertical of the eyes. 



The teeth on the jaws do not much differ from those of the Philypnus dor- 

 mitator. The vomerine patch is narrowed towards its ends, and its teeth 

 are much smaller than those of the jaws, especially anteriorly. 



The scales on the sides of the body are of an oblong form and hexagonal 

 outline, with the nucleus at the posterior angle and with about eight radiating 



I860.] 



