1869.] and Membranipora Bengalensis. 39 



years ago directed attention to the existence of those solid bodies in 

 the internal tissue of some of the species of Zoantlms, Actineria, and 

 others. In spite of the solid skeleton which I have described, I 

 must, however, remark that the softness of the body is unusually 

 great in the present species, and nobody in observing the pulpy 

 appearance of the same would suspect solid scleroicls in it. 



c. The collar, or the upper margin of the column, is generally 

 slightly marked, though always indicated by a slight contraction below 

 the upper edge. In the abnormal positions of the species, it becomes 

 occasionally much more prominent, (see figs. 6, 7, 8, and 9 in pi. X) ; 

 the muscular tissue is also much stronger on it, than on the other 

 parts of the column, and sometimes nearly hardend. The cinclides on 

 the collar are generally the largest, often forming a continuous series at 

 its outer edge, while other loop-holes are irregularly dispersed over the 

 entire column. 



cl. The disc, forming the upper part of the body, is very soft and 

 transparent ; it is only marked by radiating furrows which, strictly 

 speaking, are in the present case an essential part of the tentacles. 

 It probably consists like these only of four layers, the innermost, 

 containing the scleroicls, being wanting, or at least so much reduced, 

 as to be hardly traceable. 



e. The tentacles partially originate, according to the above state- 

 ment, at the mouth, becoming isolated some distance from it ; 

 towards the periphery they are separated from the collar by a broad 

 groove. 



In the expanded animal, they are roundish, or slightly compress- 

 ed from front to back, strongly inflated in the middle and at their 

 roots, becoming after the first half length rapidly thinner. Their 

 tips are slightly swollen or obtuse, and perforated. Externally the 

 surface of the tentacles is smooth ; but under the glass fine whitish 

 spots, indicating the presence of cnidce, may be observed (pi. X. 

 fig. la). In the primary tentacles of older specimens the whitish 

 specks are visible to the naked eye (see pi. X, fig. lb). The anatomical 

 structure (see pi. X, fig. Id) of each of the tentacles is similar to that 

 of the septa, except that they appear to want the scleroid layer. 

 They are enveloped in a soft and usually very thick, mucous outer 

 layer, being a little more consistent only at their bases. The cnidce 



