ON THE PHYLOGENY OF THE CARAPACE ETO. 791 
On the Phylogeny of the Carapace, and on the Affinities of the 
Leathery Turtle, Dermochelys coriacea. By Dr. J. VERSLUYS, 
Assistant Professor of Zoology (Zoological Institute of the 
University of Giessen). 
[Ordered by the General Committee to be printed in extenso.] 
Tue Leathery Turtle or Leatherback, Dermochelys cortacea, is of 
special interest, as its shell is absolutely different from that of all 
other living turtles and tortoises. It is either the representative of a 
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Fig. 1. Carapace of Dermochelys, dorsal view; about ;4, natural size. The mosaic 
of small plates and the marginal keel are indicated on the left half of the carapace 
only. 
ck, costal keel ; mk, marginal keel; nk, neural keel ; smk, supramarginal keel. 
very primitive offshoot of the Testudinate stem, or its shell represents 
a very remarkable modification of the common type. 
The normal Testudinata possess a carapace formed by a relatively 
small number of bony plates: the costals, the neurals, the marginals, 
a nuchal, and often one or two suprapygals; the neurals and costals 
