400 EXPLORATIONS ACROSS THE GREAT BASIN OF UTAH. 



I am able to snv, from an examination of the specimens used by Dr. Girard himself 

 for description,' that it agrees with nil allied species in having the normal number of 

 seven, which are developed as in Jloronc amcrhana. 



There are preserved in the museum of the Smithsonian Institution three speci- 

 mens of the Mnmtw iHtrmyhi, one of which was obtained bv Lieutenant Couch at 

 New Orleans, and two hu-er ones were found at Saint Louis, Mo., by Dr. George 

 Engclniann. The small specimen from New Orleans differs from the two Missouri 

 specimens bv the larger second spine of the anal fin, but in every other respect they 

 are similar. 



Family COTTOIDiE, (Rich.)- 



Subfamily COTTIN.E, (Box.). 



Genus POTAMOCOTTUS, Gi£l. 



Syfttmymy. 



Body elongated, anteriorly subcjlindrical, and thence declining in height toward 

 the caudal, where it is also notch compressed. The skin is perfectly smooth and 

 naked, except sides behind the pectorals. 



Head conical or cuneiform in profile, oval above and depressed, and covered by a 



curved upward, and below with one or two smaller ones. <»r"tnbercle's; the antero- 

 inferior angle of the sub-operculum is also armed with a spine directed forward and 

 downward. The other bones are unarmed. 



Eyes mostly situated in the anterior half of the head: frontal bones between them 

 of moderate width. 



Mouth slightly oblique, and its gape is quite large. 



Teeth villiform on the jaws and vomer as well a" palatine bones. 



Branchial aperture* vertical and oblique, entirely separated from each other by a 

 perfect isthmns, as wide or wider than the interval between the bases of the ventrals. 

 There are six branchiostegal rays. 



Dorsal Jias two, either entirely separate or connected by a low membrane The 

 first has from six to nine slender spines. 



Pectorals rounded, and their rays generally unbranched. 



Ventrals nearly under the pectorals, and have a spinous and four (rarely three) 

 unbranched rays. " ; 



The genus Potamocottus in every respect resembles the Uramelea, except in the 

 presence of a band of villiform teeth on each palatine bone. Several species properly 

 referable to this subgenus have been described as true Cottl. It is equally closely 

 related to the genus Cuttopsis of Girard, but is distinguished by its smooth skin. The 

 species named by Girard Cottopsi* (/hIoshs is a true J'otfamocottus. 



The propriety of retaining the species with palatine teeth in the genus Cottus 



