272 FOREIGN JURASSIC HOLECTYPI. 



HoLECTYPUs iNFLATus, Jgassiz. Syn. Biscoidea inflata, Agassiz, Echinoderm. Foss. 



Suisse, tab. 6, figs, 4 — 6. 

 — — Desor, Monogr. des Galerites, 



tab. 9, figs. 7—10. 



Test thin, small, and depressed, with tumid, inflated sides ; tubercles small, numerous, 

 twelve rows in the inter-ambulacra, and four in the ambulacra; miliary granules do not 

 form horizontal series ; mouth opening small and decagonal ; anal opening, very large 

 and pyriform, extending from the peristome to the border, with the apex directed 

 towards the mouth. 



Formation. — " Portlandien inferieur (Astartien) du Jura Neuchatelois. 

 "Collections. — Museum of Neuchatel. Coll. M. Gressly." Desor. 



HoLECTYPUs GiGANTEus, BesoT. Syn. Biscoidea speciosa, Agassiz, Echinoderm. Foss. de 



Suisse, tabl. 6, fig. 16. 

 — — Desor, Monogr. des Galerites, 



tabl. 10, fig. 13. 



"A very large, depressed species. The base is furnished with numerous close-set 

 tubercles, but without a regular arrangement ; mouth opening proportionally very small ; 

 anal opening pyriform, hardly occupying half the space between the peristome and the 

 border." 



Formation. — " Corallien de la Vallee de la Birse. 



" Collection. — M. Gressly ; very rare." M. Desor adds, in a note to the above 

 description, in his ' Synopsis des Echinides Foss./ that it is by mistake this species has been 

 confounded by M. Agassiz and himself with IT. speciosus, Miinst. The arrangement of 

 the tubercles is very different in IT. giganteus ; the regular concentric disposition observed 

 in H. speciosus is absent in H. giganteus; their regular distribution in the one, and 

 irregular distribution in the other, form a diagnostic character between these two gigantic 

 Holectypi. 



