i) 
a 
iS) 
DESCRIPTION OF THE SPECIES OF PTERYGOTUS 
free claw 0'” is broad, linear, and beset with numerous small teeth, 
a few larger striated ones interspersed ; the first only is seen on each 
chela, that on the fixed claw very near the angle; that on the free 
finger is more distant. 
c’, ¢, Mandibles, &c2—There are traces of two pairs of jaws, the 
palpi attached or in close proximity, figured with the rest of the 
carapace in Plate XV. [Plate 26] fig. 2. One endognath is lying 
loose on the left hand of that figure in a reversed position, and 
has the usual curved striate teeth, but nothing can be determined 
of its shape. On the opposite side two jaws with palps lie one 
over the other, and a woodcut is added below, Fig. 2, to show in 
a diagrammatic form the arrangement of these pieces with their 
appendages. 
The outer jaw g, shows the terminal serrate lobe, with at least 
seven articulated arched teeth (the uppermost largest), and about 
Fic. 2. 
Plerygotus perornatus. Mandibles, g, &; palpi, c, 2, 7, &c. The post-oral plate is 2 szta. 
This specimen is the same as that figured in Plate XV. fig. 2, but with some parts omitted. 
three times as long as the breadth at their base, and sharp pointed. 
The other, #, is pushed in advance of g, it shows a similar set, 
more displayed, of curved striate teeth ; about five are distinctly 
preserved. 
The filament c, /, which, from analogy with that of A. dzlobus, is 
presumed to be the palpus, appears to me to be connected with the 
mandibular piece g, and to cross the two others, /, 7, which seem to 
form part of a branched palpus, and to belong to a second ectognath 
(mandible or maxilla). But the connexion of these with the serrated 
pieces g or # is not quite certain; they must therefore be described 
‘In Plerygotus the large teeth are very nearly opposite one another in the middle and 
outer portions of the forceps, and must have acted as cutting blades, not merely as prehensile 
forceps (see Plate VI. [Plate 17].) 
* Discovered in this species by Professor TIuxley. But he does not agree with me, that 
there is sufficient evidence of the two pairs of jaws, one with a single, the other with a 
branched palpus (see p. 189). 
