8o PROCEEDINGS COTTESWOLD CLUB 1912 



shows no sign of the anterior elevation of the test, and the 

 apical system, though not well shown, suggests that the 

 specimen should be referred to Galeropygus and not to H. 

 ovalis Wr. 



Garantiana-'Beds, Hadspen, Somerset. 



HYBOCLYPEUS' WOOLSTONENSIS sp. nov. PI. VUI. 

 figs. 3a, b and c. 



T.l. Woolston, Somerset. 



Hor. Garantiana-Beds. r). GarantiancB. 



Colin. L. Richardson. 



Description. — A very depressed form of Hyboclypeiis, subcircular in 

 outline, with a concave base. The two posterior ambulacra do not bend in 

 towards the anal canal, but run straight across from the ambitus towards 

 the posterior end of the apical system. 



The apical system is not well shown in any of the specimens that have 

 been examined, but from what can be seen of it, it appears to be similar to 

 that exhibited by Hyboclypeiis ovalis Wright. 



Remarks. — In general appearance this species very closely 

 resembles Galeropygus agariciformis (Wright). Apart from 

 the form of the apical system, it differs from that species in 

 the straightness of the two posterior ambulacra, and in 

 being slightly more depressed. In G. agariciformis the two 

 posterior ambulacra curve in towards the anal canal. These 

 differences might be of use in identifying a specimen in which 

 the apical region was not preserved. 



The depressed circular form of the test and the absence 

 of any anterior elevation distinguishes this species from 

 Hybodypcus subgibbcndus sp. nov. {infra) and Hybodypeus 

 cf. ovalis Wright, which occur at the same horizon. 



(/«)'« )(/u(//«-Beds [gamHliancc) — Woolston. 



HYBOCLYPEUS SUBGIBBERULUS sp. nov. PI. VIII, 

 figs. 2a, b and c. 



T.l. Woolston, Somerset. 



Hor. Garantiana-Beds. r,. Garantiance. 



Colin. L. Richardson. 



Description. — An ovate, depressed form, the tost elevated anteriorly 

 after the manner of Hyboclypeits gibbeynliis, but much less conspicuously. 

 The outline of the specimen figured approaches very nearly to that of Wright's 

 figure of H. ovalis ; it is, however, a more depressed form. 



I. Detiiiled descriptions of the new species of H>'4oc/y/>f»s have not been attempted, but 

 attention is directed to those features which distinguish the species from allied .forms. The 

 detailed structure of the test (tuberculatiou, etc.) has not been studied. 



