WEST INDIAN STARFISHES 143 



spine, as long as a plate, often with a smaller spine at its base. 

 Sometimes there is a small pectinate pedicellaria between two 

 of these plates. 



The dorsal parapaxillge have roundish, flat bases, and bear 

 about thirty almost granule-like, obtuse spinules and on most of 

 them a delicate central spinelet. 



The papulae, at the base of each ray, vary from one to eight, 

 according to age. One of these is larger than the rest and is 

 situated in the median radial line. It is sun-ounded by four 

 plates, which form a cross, and they are larger than those adja- 

 cent. The other papulae are situated in the same transverse line, 

 or else a little more distal. 



The interactinal plates are six to eight and form only one row. 

 In the suture between some of them there is a pectinate pedicel- 

 laria, with six to eight papilla? ; othier pedicellariae, smaller in 

 size, may be present. 



The adambulacral plates project strongly into the groove and 

 each bears an inner marginal row of eight graded spines; other 

 smaller spines continue the rows on the actinal edges. A large 

 spine stands on the actinal side, sometimes accompanied by a 

 smaller spine. 



Several of the characters given above are due to immaturity, 

 especially the small number of papular pores, of marginal plates, 

 and of interactinal plates. M. Perrier here restricts the name 

 mirabilis to those specimens that lack long spines on the central 

 part of the disk. This feature is, without doubt, in some cases 

 due to immaturity and yet there are allied species that do not 

 have them, even when of large size. Therefore there may be 

 more than one species among the numerous small specimens list- 

 ed by Perrier as C. mirahilis, without central spines. A young 

 specimen of the same species (No. 18,470 Nat. Mus.) differs only 

 in characters due to its less development. Radii are 4""™ and 

 18"*™. Its dorsal plates are flat, polygonal, and tesselated quite 

 regularly. This feature alone is sufficient to distinguish it 

 from the young of other species of similar size. Most of the 

 larger dorsal plates have an acute, erect, central spinelet. Its 

 papular pores are single on some of the rays. In that case there 

 is only the primary pore surrounded by its four special plates. 

 On some of the rays a small pore has already appeared on one 



