a 
108 Reviews and Records in Anatomy and Physiology. 
made their escape. These freshly-escaped individuals were all 
sexless, but contained each a considerable corpus adiposum, at the 
These animals crawled about, and soon entered some damp earth, 
quent recipients of Mermis, and we have seen many specimens 0 
imals; we will now turn and glance at some of the important 
histological points as wrought out by Meissner. 
Cutaneous System.—Omitting the very full details given of 
the structure of the skin in these animals, its composition of three 
distinct layers, é&c., we will allude only to the fact that Chitine 
enters likewise into its formation. This fact is important as cor 
roborative of other observations. Chitine was formerly supposed 
to belong exclusively to the teguments of the Arthropoda, being 
particularly prominent in the skin of insects; but recent chemb 
cal analyses of the teguments of lower animals show that it 0 
curs in nearly every class of the Invertebrata.* Jt can therefore 
no longer be regarded as having diagnostic characteristics for cel 
tain classes, but sustains relations to the external dermic skeleton 
Qo 
of the Invertebrata generally, analogous to those of bone in the 
brata. 7 
four classes of Verte 
* Besides the present case we would refer to the following: Grube, Miller's Arch 
1848, p. 461, and Wiegmann’s Arch. 1850, p. 253; Schultze, Beitr. zur Naturg' 92, 
a. Tube larien, p. 33; and Leuckart in Siebold and Killiker’s Zeitsch., 1851, p- } 
2, p. 22. yi 83 2 
