BRA CHIOPODA. 
45 
(a species then known only from an imperfect interior of the brachial valve), as 
was subsequently done by Davidson and King, Dall, and Whiteaves, but it was 
simply suggested that Billings’ species might prove a representative of the 
same genus. 
Mr. Whiteaves has given {loc. cit.) figures of Rhinobolus Galtensis, which repre¬ 
sent not only a brachial valve in entire agreement with the figures published 
by Billings, Davidson and King, and with specimens in the possession of the 
New York State Museum, but also a pedicle-valve, which is referred by him to 
the same species, but which does not at all agree with the original specimen of 
Rhinobolus. It is, on the contrary, of about the same outline as the brachial 
valve, with a low, incurved umbo and a very broad margin of contact, much 
like that seen in the species Monomerella ovata and M. Greenii. Should this 
prove to be the pedicle-valve of the species, a doubt might fairly arise as to the 
propriety of including it under the genus Rhinobolus. Mr. Whiteaves’ speci¬ 
mens are from Hespeler and Durham, Ontario, and all retain the shell, but it 
does not appear that the valves have been found in connection. The original 
specimen of Rhinobolus was from Galt, and before us is a very perfect 
brachial valve from Elora, in exact agreement with those referred to Billings’ 
species, and this we are strongly disposed to consider as belonging to the same 
form, on account of the complete harmony in the degree of development of the 
platform and muscular scars. Our belief that these represent the same species 
is further confirmed by specimens before us of a distinct species of the genus, 
R. Davidsoni, sp. nov. (see Supplement), from the Niagara dolomites near Graf¬ 
ton, Wisconsin, in which are found the same imperfect development of the plat¬ 
forms, in association with a high cardinal area and erect beak. As already sug¬ 
gested, the pedicle-valve referred by Whiteaves to R. Galtensis, resembles, as far as 
it is known, certain Monomerellas, and it will be important to look for interiors 
of this form which may lead to its correct allocation. Meanwhile Rhinobolus 
Galtensis, Billings, may tentatively be regarded as the type-species of the genus. 
In regard to the generic characters of this species, the opinion held by 
Davidson and King, that they represent an extreme aberrant variation of 
