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species of U raster just mentioned, which were not before in 
the Museum collection, led me to compare them with XJraster 
rubens, and see if some more reliable distinctions might not 
be found than the slight differences of proportion and form 
on which Forbes lays the most stress. The result of this 
examination is that the strong spines with which the bodies 
of all three are beset offer at once a clear and simple means 
of distinction, their character in each species being decidedly 
different. 
The spine of XJraster rubens is club-shaped, the base 
spreading, and irregularly nodulated, the short shaft cylin- 
drical and smooth, and the head barrel-shaped and beset 
with longitudinal rows of thin triangular projecting points. 
That of U. violacea has the basal part rising in the form of a 
short wide cylinder, crowned with an irregular circle of short 
spinules, from the midst of which the spine is continued in a 
conical shape, and near its summit is armed with rows of 
triangular projecting points like those of U. rubens. While 
that of U. glaeialis has the form of a large strong cone with 
a very wide base rising from a dense circular bed of small 
blunt spinules. The apex of the cone appears truncated, 
and its sides near the top are marked with a few slight serra- 
tions. 
Entomostraca.—lxi the shell-sand from which the Fora- 
minifera were obtained great numbers of the cases of ento- 
mostraca occur. Specimens have been picked out of Cy there 
albo-maculata, angustata, variabilis, davida, convexa, im- 
pressa, pellucida,and quadridentata, the last mentioned species 
being rather common ; and besides these X have to show 
mounted specimens of about thirty forms perfectly distinct 
from one another and from those above mentioned. At pre- 
sent however, from want of knowledge of what has been 
recently done in this subject, X am obliged to pass them 
over. 
Crustacea. The collection of Crustacea before you forms 
