NO. 3 CASSIDULOID ECHINOIDS — KIER l6l 



Shape. — Small, usually less than 15 mm. long; anterior, posterior 

 margin smoothly rounded, sides straight, adapically slightly inflated, 

 with posterior surface obliquely truncated ; adorally flattened. 



Apical system. — Slightly anterior, tetrabasal (text fig. 134), four 

 genital pores, madreporite extending posteriorly, separating posterior 

 genital and ocular plates. 



Ambulacra. — Petals very inconspicuous, difficult to see on well- 

 preserved specimens; narrow with narrow interporiferous zones, 

 petals III longer than others, open, other petals slightly closed; pores 

 conjugate, outer pore slightly elongated transversely. 



Periproct. — Supramarginal, transverse, small, opening in underside 

 of large overhang, with deep transverse indentation dorsal to it; 

 opening not in this transverse indentation as formerly supposed. 



Peristome. — Slightly anterior, circular. 



Floscelle. — Bour relets strongly developed, pointed, phyllodes (text 

 fi&- 137) widened, single pored, broad, with four pores in each outer 

 series, and one to two in each inner ; buccal pores present ; sphaeridia 

 in two series along midline of each ambulacrum. 



Tiiherculation. — Adapically, tubercles very small, covering whole 

 surface, obscuring petals ; adorally tubercles larger, except for naked, 

 pitted medial area in interambulacrum 5, ambulacrum III. 



Occurrence. — Upper Cretaceous (Maestrichtian), Holland, France. 



Location of type specimen. — Unknown. 



Remarks. — d'Orbigny's (1856, pi. 927) figures of this species are 

 erroneous in several important details. He shows a wide bilobed 

 opening for the periproct, whereas in reality the opening is much 

 smaller and occurs on the lower side of the overhang, not in the 

 surface posterior to the overhang as shown in his figure. The 

 bourrelets are pointed, not bulbous, and there are very few pores in 

 the phyllodes, not many as shown in his drawing. d'Orbigny does not 

 show the naked, pitted zone in interambulacrum 5 and ambulacrum 

 III, and the petals are not as conspicuous as he depicts them. 



? Synonym of RHYNCHOPYGUS 



Paralampas Duncan and Sladen, 1882. Pal. Indica, ser. 14, vol. i, pt. 3, p. 72. 

 Type species, Paralampas pilcus Duncan and Sladen, by subsequent designa- 

 tion, Lambert and Thiery, 1921, p. 371. 



Remarks. — This genus was erected by Duncan and Sladen for two 

 species from the Paleocene of India which differ from Cassidulus by 

 having a higher test and lacking a naked medial zone in interambula- 

 crum 5 and ambulacrum III. The higher test does not seem to me 



