Putnam.] 840 [ilarch 18, 



and on the fishes of our southern waters, and one whose memory is 

 deeply cherished by those who were honored with his friendship. 



Ophidium marginatum DeKay. 



A single specimen of this rare fish is in the Agassiz Collection. It 

 is in rather poor condition, but sufficiently well preserved to estab- 

 lish the fact that DeKay's description and figure are quite correct, 

 and to enable the heretofore unknown character of the air-bladder 

 to be made out and thus settle the validity of the species. 



The species is very closely allied by its external characters to 

 0. barbatum and 0. Broussonetii from the Mediterranean, but differs 

 in a very marked manner from them in its air-bladder. 



The air-bladder, which is represented of natural size in the fol- 

 lowing cut (a, view from above; b, froin below; c, from the side), is 



thick, flattened above, and bulg- 

 ing below, about two-thirds as 

 wide as it is long; slightly con- 

 tracted at its anterior portion, 

 where it is closely united to three 

 small, thin and flat bones, which 

 penetrate its substance but do not 

 enclose the side walls, by the extension of the lateral bones, as in 

 0. Vasalli. Posteriorly the bladder is rounded, with a slight notch 

 in the hind margin, and just forward of this notch, on the under side, 

 is a round foramen covered by a very thin mucous membrane. 



Ophidium'Holbrookii sp. nov. 



The only specimen I have seen of this species was collected by 

 Mr. C. J. Maynard, at Key West, Florida, in 1872. Externally it 

 cannot be distinguished from Mediterranean specimens of 0. Brous- 

 sonetii, with the exception that when placed side by side with them 

 it is seen to be a slightly deeper fish. The barbels, length of the 

 maxillary, proportions of the eye and of the head are about the same, 

 and it also has the black margin to the dorsal and anal fins in com- 

 mon with several other species. The air-bladder, however, is of a 

 different shape, being very long and pointed, with a posterior portion 

 that is easily detached, while in 0. Broussonetii the air-bladder is 

 oval, and is quite firmly attached along the vertebral column. Had 

 I examined but a single specimen of 0. Broussonetii and a single 

 specimen of 0. Holbrookii, I should hardly have dared to consider 

 the difference in the shape of the air-bladder as one that would 



