262 HAWAIIAN AND OTHER PACIFIC ECHINT. 



Key to the Species of Echinocardium. 



Anterior ambulacrum distinctly depressed, at least at ambitus. 



Depression of ambulacrum III begins at apical system; pore-pairs of III within 

 internal fasciole in crowded series; large tubercles in interambulacra 2 and 3 



above ambitus cordatum. 



Depression of ambulacrum III begins at anterior end of internal fasciole, within 

 which pore-pairs of III are indistinct and widely separated; no large tubercles 



above ambitus mediterraneum. 



Anterior ambulacrum little or not at all depressed. 



Large primary tubercles above ambitus, at least in interambulacra 2 and 3 ; labrum 

 moderate, reaching nearly or quite to end of first ambulacral plates. 



Prominent primary tubercles above ambitus in all the interambulacra, though 



sometimes few flavescens. 



Primary tubercles above ambitus evident only in interambulacra 2 and 3 

 (sometimes a few in 1 and 4). 

 Internal fasciole large, its enclosed area about one third as long as test; 

 little or no depression of apical region. 



Posterior petals notably short (7 pore-pairs, with 10 in anterior 



petals) laevigaster. 



Posterior petals about equal to anterior (8-10 pore-pairs with 10 in 

 anterior petals). 



Mouth pentagonal scarcely 1.5 times as wide as long .... mortenseni. 



Mouth reniform, twice as wide as long dubium. 



Internal fasciole very small, its enclosed area only about one fourth as 

 long as test; a distinct saddle-shaped depression in apical region . . capense. 

 No large primary tubercles above ambitus in any interambulacrum; labrum 

 very short reaching scarcely beyond middle of first ambulacral plates . . pennatifidum. 



Echinocardium cordatum. 



Echinus cordatus Pennant, 1777. Brit. Zool., 4, p. 69. 

 Echinocardium cordatus Gray, 1848. Brit. Rad., p. 6. 



He would be a hardy zoologist who would maintain australe as a species 

 distinct from cordatum. The amount of material which has now been gathered 

 from the four quarters of the globe shows that this species is a very variable and 

 remarkably wide-spread form. No other echinoderm can compare with it in 

 its world-wide distribution. Mortensen speaks of it as cosmopolitan, except 

 for the Pacific Coast of America, but there is in the M. C. Z. collection a fine 

 specimen from Mulege Bay, Gulf of California, collected by W. J. Fisher. It is 

 worthy of note that no specimen of Echinocardium was taken in the East Indian 

 or Indian seas by the Siboga, Valdivia, or Investigator, yet the present species 

 ig commoo along the coasts of southeastern Japan and is abundant along the 



