ECHINOCYAMUS. 59 



Echinocyamus. 



Leske, 1778. AM. ad Klein, p. 149. 

 Typo. Echinocyaiyuos nngutosu-i Lcsko, np. cit., p. 1.51 = Echinus miniiliiH Pallas, 1771. Spic. Zool., 



10, p. 34, pi. 1, fig. 2.5. 



Although Mr. Agassiz, in the Revision, only recognized one species in this 

 genus, the later work of Mazetti, de Meijere, and Mortensen has shown that the 

 genus really contains a considerable group of more or less distinct species. 

 In studying the large series of specimens in the M. C. Z. collections, I discovered 

 two very distinct, undescribed species, and careful examination of the Hawaiian 

 Fibulariidae collected by the Albatross has forced me to the conclusion that 

 that small series includes two new forms. I therefore recognize at the present 

 time eleven species, but admit freely that three or four of these are difficult to 

 differentiate clearly and possibly are not valid. I have examined specimens of 

 nine species but have not seen either elegans or macrostoyyius; the latter seems 

 to be perfectly distinct, but elegans is dubious to say the least. All of the 

 species are small, specimens exceeding 10 mm. in length being quite unusual 

 although Mortensen records one 15 mm. long. The bathymetrical range of 

 the species is nearly as remarkable as their wide geographical distribution for 

 while they are chiefly confined to shallow water, at least one species occurs at 

 from 800-1,270 fms. 



Key to the Species of Echinocyamus. 



Petals well formed with .six or more pore-pairs on each side. 



Poriferous areas slightly curved and converging, at least in posterior pair of petals; 

 test closely covered with minute tubercles; primaries scattered and smaller 

 than genital pores; test not concave orally but a little depressed back of 



mouth; ocular pores smaller than genital provectus. 



Poriferous areas straight, parallel on diverging; test covered with coarser tubercles; 

 primaries larger than genital pores. 

 Petals very conspicuous reaching nearly to margin (except posteriorly) ; pori- 

 ferous areas widely divergent with ten to fifteen pore-pairs in each; 

 periproct nearer mouth than margin; test rather high, flat above, some- 

 what concave beneath; mouth longer than wide megapelalus. 



Petals less conspicuous; poriferous areas parallel or sUghtly diverging, usually 

 with fewer than ten pore-pairs in each. 

 Test flattened; apical system anterior to center. 



Test wide, its breadth rarely less than .80 of length; flat or slightly 



concave orally minutus. 



Test long and narrow, its breadth only about .70 of length; markedly 



concave orally, at least po.sterior to mouth elongalus 



