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in the best preserved hydrothecæ I have found a distinctly three- 
toothed margin and three opercular valves. 
Diphasia (Agassiz) Nutting. 
Of the nine species mentioned in Nutting's work I must 
refer D. corniculata (Murray) to Sertularia, and D. tamarisca, 
which possesses a three-toothed hydrothecal margin and three oper- 
cular valves, to Sertularella. 
Abietinaria (Kirchenpauer) Nutting. 
Of the 16 species, which Nutting refers to this genus, I 
have here to mention three, namely A. compressa Mereschk., ÅA. 
Aleæanderi Nutt. and AÅ. greenei Murray, and of the two latter 
species I have examined specimens sent to me by Prof. Nutting. 
The first-named species, which the author no doubt refers to Abie- 
tinaria becauSe of the form of the hydrothecae, is according to 
Mereschkowsky provided with two lateral teeth, and as such 
are not found in any species of that genus, I cannot doubt but 
hat it belongs to Sertularia. Å. Alexanderi is also a Sertularia, 
being provided with two lateral teeth, an angularly bent adcauline 
membrane, and an abcauline membrane, which ends with a free 
valve. : 
The hydrothecae of A. greenei are as pointed out by Nutting 
subject to great variation, the abcauline margin being in most of 
them provided with two more or less developed teeth, while a 
number of the proximal hydrothecae in each branch have a plain 
margin without teeth. The specimen examined by me seems to 
contain only dead hydrothecae, and I have found only a small 
number of opercular membranes, a few of which reached from the 
adéauline margin to the tips of the teeth, and, therefore, I am 
most inclined to refer this species to my new genus Odontotheca. 
In such hydrothecae which have no teeth the opercular membrane 
must be provided with a free abcauline margin, and this species 
therefore seems to form a connecting link between Odontotheca and 
Abietinaria. The hydrothecae are provided with a small internal 
adcauline tooth, and a similar more or less developed tooth I have 
