NO. 3 CASSIDULOID ECHINOIDS — KIER I73 



Floscdle. — Boiirrelets well developed, triangular, not vertical. Phyl- 

 lodes very broad, double pored (text figs. 145, 146), two series of 

 pore pairs in each half -ambulacrum ; few in inner series, one in 

 ambulacrum III, one or two in ambulacra II and IV, one to three 

 in ambulacra V and I : five to eight in each outer series, all pores 

 widely separated from peristome. Sphaeridia very large, approxi- 

 mately eight in each ambulacrum, arranged in double alternating 

 series ; no buccal pores. 



Tuberculation. — Tubercles, perforate, very small adapically, ador- 

 ally much larger, with deep, large, longitudinally oriented scrobicules, 

 with bosses anteriorly situated in each scrobicule ; tubercles largest 

 in paired interambulacra midway between peristome and margin, no 

 tubercles in ambulacrum III, or in anterior portion of interambula- 

 crum 5. All adoral areas devoid of tubercles, profusely pitted. 



Occurrence. — Cretaceous, Upper Albian, Upper Greensand, Black- 

 down, Devon, Warminster, Wiltshire ; Cenomanian, Chloritic marl, 

 Chardstock, Somerset. 



Location of type specimen. — Unknown ; not in the British Museum 

 (Natural History). According to Wright (1875, Cretaceous, p. 251), 

 Forbes "detected" the type in Professor Tennant's Collection. 



Remarks. — d'Orbigny (1858, p. 407) described and figured a 

 French specimen that he referred to this species. I have not seen his 

 specimen, but from a study of his figures and his description of it, 

 it does not belong to this species. d'Orbigny's specimen is much 

 larger and has a very different shape, with its greatest width posterior 

 to the center, whereas in the English specimens of Ochetes morrisii 

 the sides are parallel. The test is much higher in the French speci- 

 men, and the margin much smoother, with an anteriorly eccentric 

 instead of central apical system, much more developed petals, with 

 petals V and I straight instead of curved marginally. Adorally, the 

 French specimen lacks the well-developed floscelle, naked, pitted areas 

 in interambulacrum 5 and ambulacrum III, and the large, deeply 

 scrobiculated tubercles. This specimen is certainly not conspecific or 

 even congeneric with the English specimens. Although it may repre- 

 sent a new species, I do not erect one myself, as I have not seen any 

 specimens. 



Morphological note. — Owing to the severe weathering of some of 

 the specimens of O. morrisii, the phyllodes appear at first glance to 

 be single pored. The pores have been so enlarged that the calcite 

 separating the two pores of a pore pair is usually absent. 



