TUNICATA. 341 



Off Mxjtwal Tst,ant>. March 19: 



Mottled dark blue-black and white form. 



Off Mount Lavtnia, 30 fathoms: 

 Ordinary white L&ptoclinwm. 



< )n the Coral Reef, Galle : 



Fragments of white, grey, drab and dark purple Leptoclinids too small to 

 describe satisfactorily. 



Family: DIPLOSOMATID.E. 

 Diplosoma viride, n. sp. -Plate VIII., figs. 34 to 40, and Plate IX., fig. 6. 



Colony rounded to elongate, moderately thick, encrusting on Algse and Coral 

 fragments (Plate IX., fig. G) ; surface even and soft; colour, rich green; size, from 

 2 millims. in diameter up to 4 centims. iu leugth x 1 centim. in breadth x nearly 

 1 centim. in thickness. 



Ascidiozooids about 0"5 millim. across anterior end; arranged irregularly, in the 

 smaller colonies forming a single row round the edge (Plate VIII., fig. 34). 



Test having two distinct layers ; the spreading margin of the colony, often drawn 

 out into delicate processes (fig. 36) for attachment, is formed of highly vesicular test, 

 full of bladder cells, while the deeper part in which the ascidiozooids are embedded 

 is much denser, has no bladder cells, and is crowded with small test cells and with 

 large spherical green bodies which give the colour to the colony. 



Branchial Sac with four rows of rather small rounded stigmata (figs. 37 and 38). 

 The transverse vessels have muscle fibres. 



Tentacles six in number, all one length. 



Alimentary Canal large, stomach smooth-walled, rectum conspicuous, containing 

 three or four fascal pellets (fig. 36). 



Localities. (l) On Coral Reef, Galle ; (2) Talaivillu Paar, 8 fathoms. 



The colonies of this small dark green Diplosoma are very abundant at both localities 

 where they were found. On Talaivillu Paar thev occur growing over broken fragments 

 of Madrepores and other dead corals, and in the lagoon at Galle they are abundant, 

 encrusting calcareous and other Algae. Most of the colonies are small and rounded, 

 but some become more elongated and form small encrusting sheets. The usual 

 occurrence, however, is numerous small rounded colonies, closely placed, which may 

 cover an area up to 8 centims. x 5 centims. When alive, the centre of the colony 

 where the common cloacal aperture is placed is depressed and of a paler green colour. 

 The zone of ascidiozooids is also paler, while the outer ring of the colony, outside the 

 ascidiozooids, is the darkest and is usually of a very rich green colour (see fig. 40). 

 The preserved specimens have entirely lost their colour and are now opaque white. 



