464 G. HERBERT FOWLER. 



The whole exterior of the animal is densely covered by particles 

 of micaceous sand, Foraminifera, and sponge spicules, which 

 are firmly embedded in the mesogloea of the body-wall, after 

 tlie manner characteristic of the Zoanthese. This exterior is 

 divisible into two surfaces, of which the lower plane surface 

 appears to correspond to the limbus or pedal disc of ordinary 

 Actiniaria, but is obviously never attached in adult life to 

 stones or other large objects ; the upper and more convex sur- 

 face, and the cone, correspond to the lower part of the column. 



At the truncated apex of the cone (fig. 1) is the opening 

 through which oral disc, tentacles, &c., have been withdrawn. 

 It exhibits in many specimens eight grooves which project 

 slightly towards its centre, and which are doubtless due to the 

 contraction of the eight retractor muscles. This opening leads 

 into a tube which passes vertically downwards, and which has 

 a sandy coating like that of the exterior (cf. figs. 10, 23) ; tliis 

 appears to be the upper part of the column pulled inwards and 

 downwards in retraction, and passes into the oral disc (fig. 23) 

 from which spring the tentacles ; below this, again, is the 

 stomodseum. The relative position of the various regions in 

 retraction is, therefore, that of an ordinary Actinia, and is 

 effected in much the same manner, viz. by retractor and 

 sphincter muscles, although these are markedly different from 

 the corresponding structures in Actinia. 



It is probably attributable to the tough character of the 

 body-wall that the preserving fluid (apparently spirit) has been 

 unable to penetrate, and that the cells of the interior have 

 consequently been for the most part reduced to a pulp in 

 which their length and distribution are alone recognisable. 



In scraping off the sandy particles from the exterior surface 

 of the organism, a necessary preliminary to section-cutting, 

 but frequently detrimental to the anatomy, it is noticeable 

 that the sand tends to come away in little sheets, in which the 

 particles are cemented together by a gelatinoid substance, 

 staining uniformly both with carmine and with hsematoxylin, 

 and formed apparently of an outer layer of mesoglcea. No 

 ectoderm-cells were traceable anywhere on the exterior, a 



