50 SOLENODON PARADOXUS. 
almost straight, posteriorly diverging cerebral margins, instead of the outwardly 
bowed boundaries seen in Erinaceus, and Hemicentetes, or the concave outlines 
of Chrysochloris. The olfactory lobes are more oval, as in Hemicentetes (Leche, 
:07, p. 102, fig. 87) and the constriction between them and the cerebral hemi- 
spheres is very shallow in comparison with the condition in the Centetidae. The 
cerebral lobes do not extend back so far, relatively, as in Centetes, for the opticus 
and post-opticus are visible in dorsal view, as is true also of Erinaceus. There 
is a single well marked lateral sulcus on each of the hemispheres as in the latter, 
and in addition an ill defined sulcus dorsal to this, which may have been the 
result of poor preservation. The cerebrum of Centetes is represented as quite 
smooth. The cerebellum is longer in proportion than in Centetes, but otherwise 
much similar with a prominent vermis bounded posteriorly by a deep notch, 
and with pointed lateral prolongations directed forwards. In median section, 
directly ventral to the center of the cerebellum, two slight transverse grooves | 
mark off a well defined pyramis and anterior to it a broader pons. 
PLEXUSES. 
The brachial plexus (Plate 6, figs. 7, 10) in Solenodon paradozus is chiefly 
made up of trunks from the sixth, seventh, and eighth cervical nerves and the 
first dorsal nerve. In one individual, a slender filament was present from the 
base of the fifth cervical nerve passing posteriorly and receiving two minute 
threads from the sixth cervical nerve. In Solenodon cubanus Dobson found 
the fifth cervical to enter into the plexus as a major element. More or less 
variation is to be expected in the details of the arrangement of the nerves, but 
the chief connections were nearly identical in the specimens examined. The 
sixth nerve passes distally as a single trunk with a large basal branch to the 
seventh cervical nerve. In one instance this connecting branch had the appear- 
ance of a fusion of a basal branch from both nerves, but in the other the dual 
nature of the connection was less clear. The lateral branch of the sixth nerve | 
appears to correspond with that supplying the subscapular and teres muscles. | | 
The seventh cervical, in addition to the short connection with the sixth, and a 
similar with the eighth, from the latter of which a common trunk passes off, {, 
has a more distal bifureation, the posterior branch of which unites with a large; 
branch from the eighth cervical. The main portion of the eighth unites with, 
the first dorsal nerve to form a single short trunk, which soon gives off a smal 
posterior branch, the internal cutaneous. The plexus in Solenodon is rathe 
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