PLATE III. 



Fig. 



1. Palaocorystes Stokesii (p. 15). 



2. The same, showing a portion of the abdomen. 



3. Carapace of the same, infested with a bopyriform parasite, from the Cambridge 



Greensand. 



4. The same, with the anterior leg. 



5. 6. Specimens showing the basal joints of the legs and the footjaws. 



7. Front view of a small specimen of the same species. 



8, 9. Diagrams of the abdomen and footjaw. 



The specimens are all in the collections of Dr. Bowerbank and the author, and 

 with the exception of fig. 3, are from the Gault, at Folkestone. 



10 — 12. Upper, side, and back views of Palaoco/ystes Normani (p. 16), from " The 

 Chalk Marl, capping the fire-stone," at Ventnor, in the Isle of Wight. In the 

 collection of Mr. Norman, of that place. 



