352 ECHINOCAKDIUM PENNATIFIDUM. 



It has a high test, the ridge between the posterior ambulacra being quite 

 prominent, regularly arched as in E. flavescens, but extending as a well- 

 marked rostrum over the anal opening ; this is somewhat pear-shaped, and 

 comparatively smaller than in the other species of the genus ; the arrange- 

 ment of the anal plates is similar to that of E. tlavescens ; the apical part of the 

 odd ambulacrum is narrow, the internal fasciole being very elongated, elliptical, 

 including an extremely narrow space, the sides of the test sloping up very 

 gradually like a roof towards the apex, which is anterior, and placed at a dis- 

 tance of about one fourth the longitudinal diameter of the test from the ante- 

 rior extremity, thus differing strikingly from either E. tlavescens or E. corda- 

 tum, in which the junction of the ambulacra is either almost central or eccentric 

 posteriori}- ; the posterior ambulacra are much shorter than in E. tlavescens, 

 The whole upper surface of the test is covered with very minute tubercles, as 

 in E. cordatum, with the exception of a few larger ones along the edge of the 

 anterior ambulacral zone. On the lower side they are large, as in E. flavescens, 

 having the same general outline ; the bare actinal spaces are far wider, the tu- 

 bercles not extending so far towards the mouth from the ambitus as in E. 

 flavescens. The posterior extremity is almost vertically truncated, the plastron 

 is much smaller than in E. flavescens; the subanal plastron is less broad, 

 and higher. 



Length. Trans. Diam. Height. 



87.1 31.7 21. 



From 79-121 fathoms. 



The existence of a species of Echinocardium having the outline of Echino- 

 cardium cordatum, but the slight odd ambulacral groove of Echinocardium 

 tlavescens, is an additional proof of the identity of Echinocardium and Amphi- 

 detus, 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 

 E. mediterraneum ; not having in 1869, when the Preliminary Report was 

 written, sufficient material to make a thorough comparison which might 

 prove their identity, I gave the points of difference observed in the speci- 

 mens compared. A good figure of E. pennatifidum of Norman having been 

 given by Hodge in the Transactions of the Northumberland and Durham 

 Natural History Society, there seems but little doubt that the species I called 

 laevigaster in my Preliminary Report is the same as the E. pennatifidum 

 dredged by him on the west coast of Scotland. 



