J. E. Dueeden — Jamaican Actiniaria : Part I. — Zoanthece. 369 



species from various parts of the world, and four doubtful forms. Some of the 

 representativ.es of the genus form incrustations over the surface of univalve shells 

 inhabited by hermit-crabs, the shells being ultimately dissolved away. The colony, 

 known as a carcinsecium, retains soniewhat'the form of the shell, and contains the 

 crustacean still within. 



Epizoanthus minutus, n. sp. 



(PI. xvn. a, fig. 10.) 



Form. — Polyps cylindrical, rising obliquely or vertically from a thin, incrust- 

 ing, ribbon-like ccenenchyme. In complete retraction rounded above with a 

 small aperture remaining, but no capitular ridges and grooves distinguishable. 

 Slightly enlarged towards the base ; about the same height as breadth in retrac- 

 tion, not much more in extension ; surface rough, covered with very fine sand grains ; 

 occasionally with slight transverse wrinklings. In partial retraction swollen and 

 flat above, with the wedge-shaped, acute, capitular ridges and furrows visible, and 

 the slit-like mouth showing. In full extension the upper part of the column is 

 spread out and the middle constricted ; margin of column with fifteen or sixteen or 

 twenty-one denticulations, each with parallel sides and a straight free edge, giving 

 a castellated appearance. Disc much depressed, cup-shaped, transparent, with lines 

 of attachment of mesenteries showing through ; mouth elevated. The disc, as 

 usual, is divisible into a grooved outer part forming the walls of the cup in exten- 

 sion, and appearing as a continuation of the united bases of the tentacles, and an 

 inner, smooth, flat or slightly elevated, central part bearing the mouth in the 

 middle. Tentacles dicyclic, thin, transparent, elongated, slightly swollen and 

 rounded at the tips, outer series alternating with the denticulations, entacmseous, 

 overhanging in extension, generally thirty or thirty-two in number, but occasion- 

 ally forty-two. Ccenenchyme thin, incrusting, ribbon-shaped or irregularly 

 expanded where the polyps are closer ; surface same as that of column-wall. 

 Polyps arise independently, and may be considerably separated or more closely 

 grouped. 



Colour. — Column-wall and ccenenchyme are a dirty brown, the colour of the 

 sand particles ; denticulations with white margins ; disc brown, with darker 

 radiating lines ; tentacles transparent, several series of dark patches are present, 

 more pronounced on the outer row, tips almost opaque white. 



Dimensions. — Height of polyps in extension 0'6cm., in contraction 035 to 

 0*2 cm. Diameter in extension # 3 cm., in retraction 0*25 to 0'2 cm. Length 

 of tentacles in full extension % 4 cm. 



Locality. — Found growing in abundance near the margin of one of the 

 valves of a living Pinna shell, collected towards the eastern extremity of Kingston 



TRANS. EOT. DUB. SOO., N.S. VOL. VI., PART XIV. 3 K 



