236 



The spindles of the authocodice are smooth and bent with a few warts on a 

 small part of the convex side ; 0-35 x 0-025 ; 0-3 x 0-02. 



Locality: Andamans. Marine Survey. Previously recorded from Hyalouema- 

 ground, Japan. 



Acis ulex, n. sp. 

 Plate I. figs. 2 and 5 ; Plate IX. figs. Ca, 6b, (3c. 



Representing this species there is in the collection a beautiful dendriform 

 colony of a greyish colour, 8 cm. in height, 6 cm. and 5 cm. along the two dia- 

 meters. The main stem arises from a very much expanded base and attains a 

 height of 3'5 cm. where it measures 3"5 mm. in diameter, the basal measurement 

 being 6 mm. From this stem several small branches are given ofl' mostly at 

 right angles, curving slightly upwards and giving origin to branchlets which 

 diverge in all directions. At the end of the main stem five branches arise all 

 about one level. These curve outwards and then inwards forming elongated 

 arcs bounding a somewhat ovoidal central space. Branches arise on these and 

 all are directed outwards. The smaller twigs diverge in all directions so that 

 the whole colony reminds one forcibly of a well-developed " gooseberry-bush ". 



The coenenchyma is thin and is composed of a single layer of opaque, white, 

 warty spindles or scales forming a sort of tessellated pavement-like structure, 

 each spicule being visible to the naked eye. They do not fit closely to- 

 gether so that the dark axis shows up in the " chinks " in contrast to the white 

 spicules. On the twigs the same types of spicules occur, but here they bear 

 long spines which present a very prickly surface. 



The polyps are distributed all over the surface of the coenenchyma. They 

 are almost absent on the main stem, few in number on the larger branches, 

 abundant on the twigs. They are small and wart-like but have a rugose 

 appearance, due to the projecting spines of perpendicularly arranged spicules. 

 The anthocodife are not fully retractile. There is a well-developed ten- 

 tacular operculum based by a collaret of six or seven rows of curved warty 

 spindles. The arrangement of the spicules in the " points " of the operculum 

 is very indefinite, varying to a certain extent with the number which may be 

 anything between three and seven. Common types are (1) two enclosing an acute 

 angle with one at the base ; (2) two diverging at both ends but touching at the 

 middle, with one at the base ; (3) four arranged " en chevron," with two at the 

 base. 



The axis is horny and cylindrical in form. It is very thick at the base 

 where it is black in colour. It tapers to a hair-like fineness at the tips of the 

 twigs where the colour is yellow. 



The spicules of the coenenchyma present the following types, with measure- 

 ments in millimetres : — 



