102 BRITISH FOSSILS. 



wards, and are not crowded at their bases by the smaller teeth 

 which vary much in size, but are all of them more or less conical 

 in shape like the larger ones. The terminal mucro is lost in both 

 the specimens ; a few tubercles occur on the shaft near the end, 

 fig. 2 a. 



Endognaths and Palpi, figs. 5-8, and Plate XIII. figs. 9-11. 

 There are several specimens and they present some strong characters 

 for the species. Plate XIII. fig. 9, and Plate XI. figs. 7 and 8, 

 show portions of the palpi, and fig. 5 an endognath with its entire 

 palp attached, and in the proper position in respect of the great 

 swimming foot c. From this specimen it would appear that the 

 remarkable spines of the palpus were directed forward. Figs. 8, 9, 

 show the great size these appendages obtained. 



The teeth of the maxillary piece (fig. 6 a a*) are small, short, 

 and obliquely conical, not curved, and as in some other species 

 striate ; there are about seven distinct, and six smaller ones, which 

 last are either connected by a horny plate (as in P. anglicus, 

 Plate VII. fig. 5 6), or are confused with setse ; the state of pre- 

 servation does not permit us to decide which. The margin near 

 the teeth is punctate, indicating the presence of hairs or setse. In 

 some specimens the teeth are narrower and sharper. 



[Fig. 10, though found in the same bed, must evidently belong to 

 a distinct species, and has been already referred to P. arcuatus. 

 Fig. 11 is probably a second pair of jaws (endognaths), as already 

 indicated in other species.] 



Palpi. The great palpi (of which fig. 6 only shows the base at 

 b, and fig. 5 a nearly perfect one in situ) 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. fig. 9), obtained 

 since Plate XI. was completed, shows all the joints complete, 

 and these resemble Plate XL fig 7. in their elongate form. 

 Fig. 5 has much shorter joints and may very possibly belong to a 

 different pair of maxillae. 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, 



* Although the specimens from Church Hill look as if there were only a single process 

 to each joint, yet, as in the palpus of this species, figured in Plate XIII. 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. 



