Genus— T HALASSOGERON. 
Thalassogeeon Baird, Brewer, and Ridgway, Mem. Mus. 
Comp. Zool. Harvard, Vol. XIII. (Water-Birds North 
Amer.), p. 345, 1884 . . . . Type TJi. cJirysostoma cuhninatus Gould. 
I HAVE already given most of the history of this generic name, and would here 
point out that it differs in biU-characters from Thalassarche by the presence 
of a fleshy membrane between the culmen and the latericorn, posterior to the 
nasal openings. In the type, the culminicorn reaches right up to the frontal 
feathers, but in other species it does not. If the presence of the fleshy mem- 
brane between the culminicorn and the latericorn can be accepted as a generic 
character, then these other species should be also considered generically 
separable by the presence of the fleshy membrane between the culminicorn 
and the frontal feathers. I do not think that these should be utihsed, but 
they are certainly modifled forms which are of more than speciflc value, and 
for the use of accurate workers who admit subgenera I have introduced 
subgeneric names. 
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