NATURAL SCIENCES OF PHILADELPHIA. 271 



srolepis, Blkr. (g, Ptereleotris), and perhaps still others. These various genera 

 are distinguished by^he form of the body, length of the fins, the form of the 

 caudal, that of the head, the dentition, extent of branchial apertures, num- 

 ber, &c, of branchiostegal rays and size of scales. 



DORMITATOR LINEATUS Gill. 



Dormitator somnulentus Gill, Catalogue of the Fishes of the Eastern coast of 

 North America, p. 44. 



Not Dormitator somnulentus Gill, ex. Gd. 



The height enters about 4^ times in the total length ; the head about 4 

 times; the diameter of the eye about equals the snout and two-ninths of the 

 head's length. The caudal forms a fourth of the length; the pectoral equals 

 a fifth ; the ventral does not extend to the anus, and is rather shorter than the, 

 pectoral. 



D. VII. I. 10. A. I. 10. P. 14. 



There were, apparently, thirty-one or two oblique rows of scales, and nine 

 longitndinal ones between the origin of the second dorsal and the anal. 



The color is brownish-yellow, thickly punctulated with darker, with a dark 

 line running along the middle of each row of scales, and with a dark vertical 

 blotch on the scapular region. The head had, apparently, two dark longitu- 

 dinal bands. The dorsal and anal fins have two rows of darker spots on the 

 basal half, and a fainter one beyond ; they are also like the other fins, punc- 

 tulated with minute darker dots. 



A single specimen, about three inches long, is in the collection of the Smith- 

 sonian Institution, and was sent from Savannah, Georgia. It was referred to 

 as Dormitator somnulentus in the " Catalogue of the Fishes of the Eastern 

 coast," but it differs from that species in color, as well as slightly in pro- 

 portions. 



On the genus PERIOPHTHALMu'S of Schneider. 



BY THEODORE GILL. 



In examining the different species of the genera Periophthalmus and Boleoph- 

 thalmus, attention was arrested by the very trenchant differences existing 

 between the Periophthalmus Kozlreuteri and P. Schlosseri, which indicated gene- 

 ric distinction. It is therefore proposed to restrict the name Periophthalmus 

 to the species having the characters indicated in the following diagnosis, 

 while for the P. Kcelreuteri the generic name Euchoristopus may be employed. 

 The Periophthalminse may be distributed as follows : 



I. Teeth of jaws vertical, D. (IV XV.) I. 1112. A. I. 



1012. 



v. Scales on head and body well developed and conspicu- 

 ous. Second dorsal and anal fins nearly equal. 

 Ventral fins in adult nearly infundibuliform Periophthalmus. 



0. Scales on body and head minute. Anal fin contract- 

 ed. Ventral fins always distinct Euchoristopus. 



II. Teeth of the lower jaw horizontal. D. V. I. 24 27. A. 



L. 2325. 



*. Scales small but conspicuous Boleophthalmus. 



0. Scales very minute, inconspicuous or obsolete in front. 



(Bol. aucupatorius Rich.) Boleops. 



Genus PEPJOPHTHALMUS (Bl., Schneid.) 



Body much compressed, with the back rectilinear, gradually declining to 

 the caudal fin, to which the rectilinear inferior outline converges still more 

 slowly. Anus submedian. 



1863.] 



