SYSTEMATIC DESCRIPTIONS — CIDAROIDA. IS 



These are described without specific name and indicate that more 

 species may be found in future, but it is not thought reasonable to 

 base additional species on such meager material. Of the recognized 

 species 4 have been previously described by Cotteau in his monograph ; 

 1 species, C. tribuloides, is here recognized for the first time as occurring 

 fossil in that region, although it is abundant in the living fauna through- 

 out the West Indies; 2 species, C. peloria and C.foveata, are described 

 as new and are quite distinct from anything previously known, either 

 living or fossil, in that region. With the abundance of Recent cidarids 

 in the West Indies, it is perhaps remarkable that more species and 

 more individual specimens have not been found in the fossil condition. 

 With the limited amount of material, no attempt has been made to 

 refer the species to the minor generic divisions of Cidaris which are 

 recognized in the classification of Recent species and to some extent 

 in the fossil as well. 



Key to the West Indian Fossil Species of Cidaris. 



Primary spines short, thick, markedly fusiform, with large granules or spinelets, in 



longitudinal series or irregularly arranged C. anguilUe 



Primary spines very long, thick, smooth or with flutings only near the distal end C. peloria 



Primary spines not as above or unknown. The species are separated on characters of 

 the test. 



Interambulacra with conspicuous sunken pits in median line C. foveala 



Interambulacra without such pits. 



Pores of a pair in an ambulacral plate widely separated, distance between them being 



much greater than diameter of pore; pores of a pair connected by a 



furrow; coronal plates well covered with tubercles and granules. . C. loveni 



Pores of a pair in an ambulacral plate not widely separated; pores of a pair not 



connected by a furrow. 



Coronal plates numerous (7 or 8), low and wide; areola; not half as wide as 



coronal plates; scrobicular circle inconspicuous C. clevei 



Coronal plates more than 6 only in very large specimens, areolae half as wide as 

 plate or more; scrobicular circle inconspicuous. 

 Ambulacra wide (one-third to one-half width of interambulacra); coronal 



plates rather sparsely covered with tubercles C. melitensis 



Ambulacra narrow (about one-fourth width of interambulacra); coronal 



plates with rather crowded tubercles C. tribuloides 



Cidaris anguillse Cotteau. 



(Plate 1, Figure 1.) 



Cidaris anguilltz Cotteau, 1875, Kongl. Svens. Vet. Akad. Handl., vol. 13, No. 6, p. 11, 



plate 1, figs. 17, 18. 

 Cidaris melitensis Guppy (pars), 1882, Scientific Assoc. Trinidad, Proa, part 12, p. 194. 



The following is from the original description of this species: 



Test unknown. Spine of medium size, elongate, cylindrical, subfusiform, 

 provided with thorny granules, sometimes very projecting, disposed in 

 regular longitudinal series. The extremity of the spine is truncate and 

 the granules elongating, form small, flattened- extensions, suggesting a 

 star or corolla. Collar distinct, finely striate, ring prominent. Articular 

 facet non-crenulate. 



The Washington specimen measures 12 mm. in length and 3 mm. in 

 diameter. It is somewhat shorter than Cotteau's measurement and 



