260 DESCRIPTION OF THE SPECIES OF PTERYGOTUS 
6, and fig. 5 a nearly perfect one ¢v szf) are broader at their base 
than the length of the serrate border a. They consist of only five 
joints, all except the basal one bearing (a pair? of) curved processes, 
while the terminal one, g in fig. 8, might even be considered as an 
additional joint! The specimen (Plate XIII. [Plate 24] fig. 9), 
obtained since Plate XI. [Plate 22] was completed, shows all the 
joints complete, and these resemble Plate XI. [Plate 22] fig. 7, 
in their elongate form. Fig. 5 has much shorter joints and may very 
possibly belong to a different pair of maxilla. In this figure, the first 
joint is very broad and large, subquadrate, tapering but little, rather 
longer than broad, and bears apparently no curved process. Its 
edge is spinose, fig. 6 6. The third, fourth, and fifth are, in figs. 5 
and 8, not very different in size and nearly square, while in fig. 7 the 
proportions are longer. ll have the great curved spines placed about 
the middle of the joint. 
In the perfect palpus (Plate XIII. [Plate 24] fig. 9) the propor- 
tions of the joints are as follows. The basal one is smaller than the 
second, about two-thirds its length, and of a roughly triangular or 
trapezoidal shape, the base smallest. The second is longest—half as 
long again as its breadth; the third and fourth much shorter, the 
fifth only half as long as broad, and bearing one curved spine at its 
outer angle, and the other (¢) at its tip. The second, third, and 
fourth joints are subcylindrical, convex on their outer margin, and 
bear the curved spines about the middle of the joint. 
The terminal articulation (g), if it be a separate joint, consists only 
of the curved process; but it is probably only the opposite spine of 
the fifth joint, seen obliquely, and in this view there would be five 
joints only to the palpus, each joint bearing a pair of processes, as is 
certainly the case in Plate XIII. [Plate 24] fig. 11. 
The processes themselves are directed obliquely outwards and 
forwards ; they are long, curved, sabre-shaped, and much compressed, 
fully three times as long as the width of the joints, to which they 
are attached by a swelled base. They are striated longitudinally, 
the striz, eleven or twelve in number, sharply impressed, not con- 
tinuous except near the tip, but interrupted alternately (Plate XIII. 
{Plate 24] fig. 10) for wide spaces, so that the number of striae 
appears little more than half what it really is. Nor are the striae 
quite parallel to the sides, for they abut obliquely against the concave 
' Although the specimens from Church Hill look as if there were only a single process to 
cach joint, yet, as in the palpus of this species, figured in Plate XIII. [Plate 24] fig. 11, 
there is a pair of these organs, it is most likely all the other specimens had two. In this view 
the two processes /, g, would belong to the terminal fifth joint. 
