59 
and is slightly inflated at the lower border. The second segment 
is narrower than the first, and prolonged obliquely backwards ; 
it is separated from the first by a shorter very deep groove, and 
from the posterior by a longer and shallower furrow. The third 
region forms nearly one half of the entire cephalothorax, and is 
bounded posteriorly by a graceful sinuous line which passes 
round the hinder border, where it played under the first 
abdominal somite. Fig. 1 gives a lateral view of the cephalo- 
thorax of Eryma Guise’, Wx., showing the deep transverse lines 
which divide the carapace into three regions. Unfortunately 
the outer lamina of the crustaceous covering is absent in the 
figured specimen, so that the prominences appear as depressions, 
whilst in another and better specimen lately collected, the entire 
surface is covered with pointed granulations, which are largest 
and most prominent on the tergal region and diminish in size on 
the lower part of the flanks. The lower portion of the middle 
region has a kind of supplementary inflated portion, and the 
upper half of its.side has a second oblique line, shorter and 
shallower than the divisional line. The tergal region (Fig. 2) 
exhibits the three divisions of the cephalothorax, and the oblique 
course they all take backwards. This view of the cephalothorax of 
Eryma Guise closely resembles the same region of the cephalo- 
thorax in Eryma elegans, (OPPEL.) (Mittheilungen, Tab. 1Vv., 
Fig. 7.) a species which is found in the Inferior Oolite of Pipf, 
near Bopfingen, (Germany.) 
The interest attaching to this fossil is great, inasmuch as it 
shows that Astacomorphous Crustacea were contemporary with 
the coral builders of our lower Oolites, and that they have come 
down through Jurassic, Cretaceous and Tertiary times into our 
present rivers, with a marvellous persistence in their typical 
structure, and exemplifying in another class of the Articulata 
that persistency of form in animal types which the Anthozoa, 
Echinodermata and Mollusca so abundantly afford. 
