BRITISH FOSSILS. 



3 



A young specimen exhibits different proportions ; it is one inch 

 and -j-'g ths in length, by 1 inch and -^-^ths in breadth. Its height is 

 three fourths of an inch. 



Locality and Geological Position. The specimens in the collec- 

 tions made by the Geological Survey are all from the Inferior Oolite. 

 They are from the pea-grit of Crickley Hill in Gloucestershire, where 

 they occur in company with the rarer Hyhocly^nts caudatus ; from 

 between Wayford and Seaborough in Dorsetshire, where they are 

 accompanied by Dysaster ringens and Gcderites (Holectypus) liemi- 

 sphericus ; and at Camlong Down near Uley Bury. 



Hyhoclypus gibberulus has been met with during the progress of 

 the survey near Bridport, and in two other localities in Dorsetshire. 



In figuring this species we are much indebted to Dr. Wright for 

 his kindness in permitting us to make use of some fine exo.mples in 

 his possession. 



Explanation of Plate IV. 



rig. 1. A large specimen of Hyboclypus agariciformis seen from above, 

 rig. 2. The under side of a smaller example. 

 Fig. 3. Terminal view. 



Figs. 4. and 5. Outlines of a less expanded specimen. 



Figs. 6, and 7. Ayomig specimen, much more convex. 



Fig. 8. Dorsal ambulacral and interambulacral plates. 



Fig. 9. Ambulacral and interambulacral plates of under surfoce. 



Fig. 10. Arrangements of the apex and anal groove. 



Figs. 11. and 12. Tubercles and granules. 



Edward Forbes. 



Octoher, 1852. 



