MUSEUM OF COMPARATIVE ZOOLOGY. 277 



tus and Echinocardiuin, based upon the isolation of the anal from the sub- 

 anal fasciole, and thus separating the group with a deep anterior groove from 

 these with a slight anterior groove is untenable. The presence of three spe- 

 cies of Echinocardiuui on both sides of the Atlantic is certainly remark- 

 able, but I am unable to distinguish the fragments of specimens unmistak- 

 ably identical with a fine specimen of Echinocardium ovatum collected at 

 Charleston, S. C, in the Museum collection, from European specimens of 

 this species. 



Off Charleston bar ; Florida in 1 28 fathoms. 



Echinocardium lsevigaster A. Ag., nov. sp. 



The existence of several species of Echinocardium having the outline of 

 Echinocardium cordatum, but the slight odd ambulacral groove of Echino- 

 cardium ovatum, is an additional proof of the identity of Echinocardium 

 and Amphidetus, as they had been limited in the Museum Bulletin, No. 2. 

 The present species, of which but a single specimen was collected, is closely 

 allied to the Mediterranean E. gibbosum. Not having sufficient material to 

 make a thorough comparison, which may prove their identity, I give the 

 points of difference observed in the specimens compared. The abactinal 

 ridge between the posterior ambulacra is quite prominent, extending as a 

 well-marked rostrum over the anal opening ; this is pear-shaped. The ar- 

 rangement of the anal plates is similar to that of E. ovatum ; the apical por- 

 tion of the odd ambulacrum is narrow, the fasciole being elongated, ellipti- 

 cal ; the sides of the test slope up very gradually from the ambitus ; the 

 apex is anterior to the centre ; the whole upper surface of the test is covered 

 by minute tubercles, with the exception of a few large ones along the edge 

 of the ambulacral groove. The bare spaces of the ambulacra on the lower 

 surface are very broad, the subanal plastron projects beak-like from the 

 posterior extremity, which is nearly vertically truncated, but the beak is 

 not as prominent as in E. gibbosum, where it becomes a striking feature. 

 From 79 to 121 fathoms. 



Echinocardium Kurtzii Gir., Proc. Bost. Soc, 1852. 



Syn. Echinocardium ampliflorum McCr., P. Foss. S. C, PI. 2, fig. 2. 



" " pothicum McCr. " " " PI. 2, fig. 3. 



" ? " cordatum Gray, Cat. B. M. 



Girard has described as Echinocardium Kurtzii a species from Charleston 

 (it occurs also in N. C.) closely allied to the European E. cordatum. Frag- 

 ments of it were collected by Mr. Pourtales, and it may be interesting to 

 compare our American species, of which the Museum possesses excellent 

 series, with E. cordatum, with which future investigations may yet prove it 

 identical, as the differences are confined almost entirely to a portion of the 



