NO. 3 CASSIDULOID ECHINOIDS KIER 1 75 



should be referred to Rhyncholampas. The fourth, C. trojanns, is 

 small but has more developed phyllodes than are usually found in 

 Cassidulus. This species, like several others, has characters of both 

 Cassididiis and Rhyncholampas and cannot be referred definitely to 

 either. These intermediate forms blur the distinction between the 

 two genera. 



There are three American west coast species that belong to Cassid- 

 ulus: C. ellipticus Kew, C. calif ornictis Anderson, and C. ynesensis 

 Kew. I have studied all the type specimens of these species, which 

 are in the Museum of Paleontology at Berkeley, Calif. The two 

 cotypes of Cassidulus ellipticus Kew are both poorly preserved, but 

 the specimen figured in Kew's (1920) plate 39, figure 3a, c, d, 

 shows the adapical surface and is herein designated the lectotype. 

 The phyllodes are not visible on either of these specimens, but from 

 the small size of the low and very elongated test, supramarginal, 

 transverse periproct, and monobasal apical system this species should 

 be referred to Cassidulus. The neotype of Cassidulus californicus 

 Anderson also should be referred to Cassidulus. Although the speci- 

 men is poorly preserved, enough of one of the phyllodes is visible 

 to see that it is very simple, with only one pore occluded in each 

 half -ambulacrum. The test is small and elongate, and the apical sys- 

 tem is monobasal. The specimen figured by Grant and Hertlein 

 (1938, pi. 4, fig. 7; pi. 30, fig. 7) is wrongly referred by them to 

 C. californicus. It differs from the latter in having a much larger, 

 more inflated test, strongly lanceolate petals with more unequal porif- 

 erous zones in each petal, more anterior apical system, more marginal 

 periproct lacking an adapical overhang, a less depressed peristome, 

 and less developed bourrelets. Apparently it is a new species of 

 Rhyncholampas. 



Kew's Cassidulus ynesensis is represented by one very poorly pre- 

 served specimen which is slightly crushed, with a large part of the 

 adapical surface missing, and so badly weathered that no details are 

 discernible of the phyllodes. Kew referred this species to RJiyn- 

 chopygus, but since it has a monobasal apical system, it is a Cassidulus. 

 Grant and Hertlein (1938, p. 109) consider C. ynezensis as a syno- 

 nym of C. californicus, but the two species are quite distinct. C. 

 ynesensis is larger, lower, with sharper margin, smaller peristome, 

 and narrower petals. 



Range and distribution. — Eocene to Recent of worldwide distri- 

 bution. 



