ALCY0NAR1A. 273 



DESCRIPTION OF THE SPECIES. 



Order I. : STOLONIFERA. 

 Family: CORNULARIID^E. 

 Clavularia niargaritiferae, n. sp. Plate III., fig. 8. 



The stolon consists of a number of thin and narrow branching threads, forming a 

 network on the surface of a pearl-oyster shell. The strands of the stolon vary in 

 breadth from 0"4 millim. to - 6 millim. They do not form any membranous expansion. 

 The polyps arise vertically from the branches of the stolon at intervals of 2 millims. 

 to 2 - 5 millims. ; there does not seem to be any interpolation of new polyps among 

 the older. 



The polyps measure 3 millims. in height, with a distal diameter of* - 9 millim., and 

 a proximal of - 5 millim. to 0'65 millim. They are thus broader than the stolon 

 branches, cf. Clavularia reptans, Hickson (1895). They have, in all cases, their 

 crowns retracted ; there is no indication of longitudinal grooves or lines. 



The walls of the polyps and of the stolons show thickly crowded spicules of minute 

 size (0-06 millim. to 0-07 millim. X 0-(J3 millim. to 0-04 millim.) interlocked by their 

 wart-like projections, cf. Clavularia Jlava, Hickson (1895). Most of the spicules are 

 substantial rods bearing blunt wart-like projections often in a whorl of four towards 

 each end. The short and simple tentacles, bearing a few blunt pinnules (not 

 sufficiently fixed to allow of precise examination) are supported by numerous 

 longitudinally disposed elongated and curved rods, which may measure - l millim. in 

 length. They are smooth and only occasionally bear projections. All the spicules 

 are colourless, and the whole colony is white in its preserved condition. 



Locality : Pearl banks, Gulf of Manaar. 



Family: XENIID^. 

 Xenia ternatana, Schenck. 



A single specimen attached to a sandy worm-tube, with polyps in three groups, 

 agrees on the whole with Xenia ternatana, Schenck, notably in having only two 

 rows of pinnules on each side of the tentacles, and about 1 8 slender pinnules in each 

 row, as also in the measurements of the polyp-body and of the tentacles. 



Xenia umbellata, Sav. 



Attached to the substratum of another specimen, which we unfortunately omitted 

 to note in the business of assortment, there was a species of Xenia which appears to 

 be referable to A', umbellata. The locality was low water at Pamban. We assume 

 that the presence of only two species of Xenia in the collection simply means that 

 Professor Herdman's work was outside the ATmm-zone. There must be many species 

 of Xenia in Ceylon. 



2 N 



