124 CEYLON PEARL OYSTER REPORT. 



Phylactocarps (fig. 3b) of the same length as the hydrocladia, occurring at intervals 

 up the branches among these, a hydrotheca at the base, succeeding internodes being 

 alternately barren or with a spine which has a large flattened gonotheca at its base. 

 The spines all turn to the same side. 



Locality : Off Galle and onwards up the west coast to Kaltura and Mount Lavinia. 



There are only pieces broken from the tops of colonies of this form, and they appear 

 to belong to a large species. In some respects they resemble Lytocarpus secundus, 

 but the branches are not so closely set on the stems and have not such a one-sided 

 mode of growth, and are about h an inch longer, ^o of an inch instead of yq. Also 

 the phylactocarps in L. secundus are only half as long as the hydrocladia, while here 

 they are as long, and the hydrotheca at their base is not described as being present in 

 L. secundus. 



Lytocarpus plumosus, n. sp. Plate III., figs. 2 to 2b. 



Trophosome. Colony about 2 inches in height, unbranched, plumose (fig. 2) ; the 

 stem monosiphonic, of a dark brown colour. Hydrocladia closely set, - x % of an inch in 

 length, pale yellow, given off alternately to right and left from the front of the stems, 

 one to each internode, which carries besides two cauline nematophores, one at the 

 base of the hydrocladia and one below it. Hydrotheca? (fig. 2a) fairly deep, narrowing 

 downwards from the rim, which is toothed, one small tooth in front and two on either 

 side. Mesial nematophores about the height of the hydrotheca?, free and spout-like 

 near the top. Intrathecal ridge sloping upwards, from low down posteriorly to about 

 opposite the middle of the nematophore. 



Phylactocarps (fig. 2b) scattered up the stems, about half as long as the hydro- 

 cladia. They have one hydrotheca at the base of each and spines, branching to either 

 side alternately, above it. 



Gonosome. Gonotheca? at the bases of the spines, one to each. 



Locality : Growing on worm tubes from the Gulf of Manaar. 



