360 Proceedings of the Royal Irish Academy. 



(6) Smaller double-clubs, with a longer constxiction, with more open heads, 



and with the warts less symmetrically arranged : 006 X 0034 ; 



0-05 X -031 ; 0049 x 0027. 

 (c) Elongateil double-clubs, tending towards double-spindles, with rounded 



blunt ends: 0091 x 003S ; 0087 X 0034 ; 0083 X 0034. 

 ((/) Elongated double-spindles, with pointed ends, and with a definite 



constriction: O'llS x 0-034; 0114 x 0-31; 0114 x 0023; 



0103 X 0023. 

 (e) Long epindles with a hint of constriction : 0125 X 0-23 ; 



0-114 X 0-031. 

 (/) Shorter spindles also with a hint of constriction: 0095 x 0019; 



0-087 x 0-015 ; 0016 X 023. 



We have little hesitation in defining (<»), (6), and (c) as distinct types ; 

 but it is just possible that (/) might develop into (<) or (d) according as 

 increase with growth was greater in length or in breadth. So many of each 

 kind occur, however, that we feel justified in defining them as separate for 

 the present, at any rate, until- more is known with regard to their growth. 



The colour of the coenenchyma is a bright orange-red — but the tips of 

 the verrucae are more reddish. 



Locality. — Laccadives, 30-40 fathoms. 



Diagnosis, c-olony simple ; spicules contain double-clubs and double- 

 spindles, with transitions to spindles. The coenenchyma is thin, and 

 contains /oMr main longitudinal canals. The verrucae are disposed in /o!/r 

 definite longitudinal series, separated by four bare tracts, which correspond 

 in position to the four main canals. The colony is markedly square in section. 



XXXI. Genus Hicella emend. 

 (a) Discussion of the Genus. 



This genus was established by Gray in 1870 (Cat. Lith. Brit. Mus., p. 40) 

 in the following terms : — 



Coral fan-like, in one plane, branched ; branches forked, rather diverg- 

 ing. Bark smooth, brown. Polyp cells cylindrical, truncated, diverging 

 from the stem at nearly right angles , mouth open. Axis calcareous, wh ite 

 solid. 



To this genus he refers a specimen under the name Nicella mauritiana, 

 and gives as a synonym his pre\ious Scirpearia dichotoma (P.Z.S., 1859, 481-2). 



Ridley (xxix, p. 130) identified a specimen from Mauritius under the 

 name iVifW/a dichotoma, and made the following observation on the spicules : 

 "There is a dense cortical layer of small double-heads and a subjacent 



