1874.] 



341 



[Putnam. 



prove of specific importance, but two specimens of Broussonetii agree 

 precisely in their bladders, and the well known and singular variation 

 of this organ in the species of the genus, as shown by the dissections 

 of Miiller, is quite convincing in the determination of the present 

 species. As in Broussonetii, the front part of the bladder is firmly 

 attached to the anterior vertebras, but in HoTbrookii this part of the 

 bladder is thicker, and is penetrated by a small bone on each side 

 anteriorly, and firmly united to the processes of the fourth vertebra. 

 The shape of the air-blad- 

 der is given in the accom- 

 panying figures; a, repre- 

 senting the surface that 

 lies along the vertebral 

 column; b, as seen from 

 the under side; and c, giv- 

 ing the profile. The air- 

 bladder is without a pos- 

 terior foramen, and in this 

 respect, as well as in its 

 being more elongated than 



those having the foramen, the species is more closely allied to 0. 

 barbatum, Broussonetii and brevibarbe. 



The 0. brasiliense, with which the species should be compared, is 

 said to have only the dorsal fin edged with black, and very short 

 barbels. The air-bladder of this species is not known. 



The teeth on the jaws are about the same in all the species of the 

 genus I have examined, but there is a slight variation in those of the 

 palatines, and more especially of the vomer, O. Holbrookii having a 

 considerably less number of the rounded vomerine teeth than any of 

 the other species mentioned below. 



The following are the characteristics of the several species of the 

 genus Ophidium which J have had an opportunity of examining. 

 The species were first determined from their air-bladders by the aid 

 of Miiller's figures. I cannot refer any of the specimens to 0. bar- 

 batum from the Mediterranean, and I have not seen O.brevibarbe and 

 0. brasiliense, both from the Brazilian coasts. 



O. Broussonetii Miiller. 



Inner barbel about two-thirds the length of the outer. Outer 

 barbel equal to the distance from the centre of the eye to the point 



