REPORT ON THE ACTINIARIA. 47 



Habitat. — Station 135a, oft' Iiiaceessil)le Island; October 16, 1873; GO-90 fathoms; 

 hard ground, shells, and gravel. 



Dimensions. — Height of the polj^s, 0'4-0'8 cm. ; breadth, 0'2-0'4 em. 



Colour. — Brownish-yellow. 



" From the material at my disposal, which appears to have been carelessly detached, 

 the general form of the present species cannot with certainty be inferred. The greater 

 part of it consists of single individuals, in which one can recognise the forcible detach- 

 ment from the colony. One group, which to all appearance represents a complete 

 and intact colony, is composed of four individuals ; they are situated, in a row and at 

 short intervals, on a thin coenenchyme which is extended like a ribbon ; their dimen- 

 sions are 4-8 ram. high by 2'5-4 mm. broad. All the polyps are strongly contracted; 

 the body-wall forms above, in this condition, an obliquely-angled ridge projecting 

 outwards ; its upper surface presents an elevation, rendered obvious by a circular furrow, 

 in the centre of which the aperture to the interior is recognisable. From the middle 

 of this upper surface radiate outwards 15-20 furrows, which are continued over the 

 projecting ridge on to the vertical body-wall, where they then flatten out. The colour 

 of the polyps is a dirty yellow. 



" The integument is furnished with accretions, and exhibits a rough shagreen-like 

 exterior. On rubbing away the thin sandy layer, there remains the thinner soft part 

 of the mesogloea, which is excellently fitted for the preparation of longitudinal and 

 transverse sections with a razor. 



" The soft mesogloea is of considerable thickness, and consists of a homogeneous 

 matrix, in which come into view the large number of cavities charged with cells. 

 These may be simple, i.e. preserve their roundish or elliptical outline, or, as in most 

 cases, may branch to form a system of anastomosing canals which entirely recall 

 Zoanthus. Below the endoderm such a canal runs in an almost unbroken ring 

 through the whole of the body-wall ; it lies so close under the epithelium as to be 

 separated from it only by a narrow lamella of homogeneous matrix. Its diameter is 

 not constant throughout its whole circuit, but is frequently constricted, and occasion- 

 ally such constriction produces an actual discontinuity. It is further of importance 

 that the canal invariably jjresents a considerable hollow expansion under each mesen- 

 terial insertion. At many points can be demonstrated a communication between 

 the smaller branching cell-canals and this large ring-canal, the latter being at such 

 places apparently expanded into a kind of funnel. Further, there are found in the 

 mesogloea numerous mesogloeal cells, giving off" fine processes ; and, finally, deUcate 

 nucleated fibres, the course of which, however, is here not radial, but in the main 

 circular. 



" The structure of the coenenchyme agrees in all respects with that of the body- 

 wall, except for the fact that it possesses endodermal connecting tubes. 



