REPORT OF DHE DIRBETOR, [O22 119 
A HEMIASPIDAN CRUSTACEAN FROM THE NEW 
YORK SILURIAN WATERLIMES 
BY JOHN M. CLARKE 
Little by little the Bertie waterlimes of western New York, 
which make the terminal member of the Silurian series, have 
revealed the genera of that singular group of crustaceans or 
arachnidans which have been for the most part originally 
described from the Silurians of the Island of Oesel in the Baltic; 
Lanarkshire in Scotland and Ludlow, England, and which have 
been called, taken together, the Bunodomorpha. They represent 
——— Se, 
Fig. 1 Hemi- 
aspis stage of 
embryo Limulus 
Fig. 2 Hemiaspis? vricnsis +» 
nov. 
small creatures of merostome (hence arachnid) structure which 
could not have been very abundant in the Silurian seas, as species 
and genera are few in number and individuals. Every new link in 
this group which helps to tie up the New York formations with 
those of the Eastern hemisphere is worthy of record. 
Of the genera (1) Neolimulus, (2) Bunodes, (3) Hemiaspis 
and (4) Pseudoniscus, all of which were described first from 
Europe, only Pseudoniscus has been found in the Bertie water- 
limes (P. roosevelti Clarke). Bunaia (B. woodwardi 
Clarke, Buffalo) is an adjusted representative of Bunodes, as is 
