J. M. Clarke—New Devonian Crustacea. 125 
rande, with this characterization. “Carapace composed of 
three pieces, or apparently of three, two of which are semi- 
circular, with the anterior end of each obliquely truncate, form- 
ing, when the two are united, an anterior triangular notch into 
which the third or rostral plate is inserted; surface concentri- 
cally marked by growth lines; no nodes or ridges.” None of 
the sections in this classification cover in as many particulars 
as this, the genera here and heretofore described by myself, and 
the description is quoted in full to emphasize the fact that, 
though the absence of the rostral piece can be regarded as only 
negative evidence, the unity of the carapace will preclude their 
observations on new forms of the Ceratiocaride from the Penn- 
sylvania Devonian, and in the loan of bis beautiful drawings 
for comparative stu ¥- 
Smith College, Northampton, Mass. 
