180 ON THE ANATOMY AND AFFINITIES OF 
eight segments connected together, but there is no evidence as to the 
total number composing the body of P. anglicus. 
4. The Telson.—Reasoning from the analogy of P. acuminatus, 
&c., the part figured in Plate V. [Plate 16] fig. 6, must be the 
telson, or terminal segment of the body, of P. anghcus. It is particu- 
larly described in the systematic portion of this Monograph (p. 233). 
I will merely remark, therefore, that it is oval, truncated anteriorly, 
mucronate posteriorly, and serrated along the lateral edges. It 
presents traces of a median ridge, and appears to have been very 
flat. 
5. Lhe Paired Appendages—The remains of three distinct kinds 
of paired limbs, besides single appendages, have been discovered in 
the same beds with the carapace and body segments of P. anglicus. 
These are :— 
(a.) The chelate organs figured in the most perfect state in which 
they have yet been discovered in Plate VI. [Plate 17] figs. 4, 5. 
Three joints at least may be observed in this member. The first is 
an elongated subcylindrical stem, flattened by pressure. The next, 
short, enlarged, and swollen, is produced into a long slender process, 
pointed and incurved at its extremity, and beset with very strong 
and numerous, unequal, striated teeth. The third joint is articulated 
with the enlarged basal part of the second, so that its similarly 
incurved extremity is opposable, like a thumb, to the latter. It 
possesses teeth of a similar structure to those in the other ramus of 
the chela, and opposed to them as the canine teeth in the upper jaw 
of a mammal are opposed to those in the lower, passing, that is, 
behind the others, or on their proximal side. 
(6.) The second kind of appendage (Plate VII. [Plate 18] figs. 
4, 5, 6, 7,) presents a large flattened basal joint, produced at one 
extremity, and truncated obliquely to its long axis at the other. The 
truncated margin is slightly curved, and is beset with Jong and strong, 
curved and pointed teeth, which are longer at one end of the series 
than at the other ; and are so constricted at their bases as to appear 
to be articulated with the basal joint. 
Of the two longest margins of the latter, the one has a general 
convexity, while the other is concave. The outer part of the former 
exhibits a sort of notch or step, in which is lodged the basal joint 
of a long palpiform appendage. This joint (¢) is very short and 
somewhat swollen. 
The next articulation (@), longer and subcylindrical, is broader 
distally than proximally. The third (e), twice as long as the last, 
has a nearly equal breadth throughout. It is exhibited 7 stu, and in 
