ECHINOCARDIUM PENNATIFIDUM. 351 



odd ambulacral zones are at first two single rows of pores (PI. XIX. f. 15), 

 which by closer crowding eventually alternate, but are not arranged in 

 pairs (PI. XIX. f. w). 



Echinocardium flavescens 



Spatagus flavescens Mull. 177G. Prod. Zool. Dan. 



! Echinocardium Jiavescens A. Agass. 1872. Rev. Ech., Pt. L 



PL XX. f. 3,4- 



Test oval ; stouter than in the other species of the genus ; seen in profile 

 quite regularly arched, though truncated at the posterior extremity, the 

 posterior interambulacral ridge extending over the anal system. The ambu- 

 lacra are very slightly sunken, not as much as in E. cordatum, but more 

 than in E. mediterraneum ; the anterior one is frequently nearly flush with the 

 test. The abactinal pole is nearly central. The internal fasciole is ellipti- 

 cal, remarkable for the great breadth of the space it encloses. The actino- 

 stome of this species and of E. pennatifidum is not narrow and transverse as 

 in the species mentioned above ; it is broader, with a straighter posterior lip. 

 The anal system is large, slightly elliptical, transverse. The color, when 

 alive, is pinkish. 



An examination of young specimens of Echinocardium cordatum shows that 

 the generic distinction which I attempted to make between Amphidetus and 

 Echinocardium, based upon the isolation of the anal from the subanal fasci- 

 ole, and thus separating the group with a deep anterior groove from these 

 with a slight anterior groove, is untenable. The presence of two identical 

 species of Echinocardium on both sides of the Atlantic is certainly remark- 

 able, but I am unable to distinguish the fragments of specimens collected by 

 Mr. Pourtales and unmistakably identical with a fine specimen of Echinocar- 

 dium flavescens collected at Charleston, S. C, in the Museum collection, from 

 European specimens of this species. 



— to 1 28 fathoms. 



Echinocardium pennatifidum 



Amphidotus gibbosus (Barrett), 1857. Ann. Mag. N. H., XIX. p. 32 (non Agass.). 

 Echinocardium pennatifidum Norm. 1KG8. 4lh Dredg. Rept. 



PI. XX. f. 1, 2. 



This species combines the general appearance of Echinocardium mediterra- 

 neum with the structure of E. flavescens. Its outline resembles that of E. cor- 

 datum, but it has, like E. flavescens, the anterior ambulacrum scarcely sunken. 



