312 CEYLON PEARL OYSTER REPORT. 



the test as a coherent shell, so as to give the appearance of one test lying within 

 another (fig. 26). In life the siphons are very long, and their terminations are yellow 

 tubes, marked with dark red bands. 



Eleven young fishes were found in the peribranchial cavity of one specimen from 

 off Mount Lavinia. 



Microcosmus longitubis, n. sp. Plate II., figs. 32 to 35. 



External Appearance. The body is ovate, with two very long siphons diverging 

 from the narrow anterior end. It is encrusted with sand and shell fragments, which 

 are especially large and thickly placed on the rounded posterior half of the body 

 (fig. 32). Size, about 5 centims. from the end of the branchial siphon and 3 centims. 

 across the wider posterior part of the body. 



Test stiff and leathery, ranging up to 2 millims. in thickness. Greyish white and 

 glistening on the inner surface, white in section. There are numerous large vessels, 

 and there are long branched processes on the surface to which the sand is attached. 



Mantle strong, very muscular (fig. 33), the body with the test removed having the 

 appearance of a ball of tightly wound threads, with the two very long siphons 

 protruding. The branchial is the longer and straighter, the atrial being curved 

 dorsally. 



Branchial Sac with six folds on "each side; rather narrower than those of the last 

 species, and having four or five bars, but none in the interspace. There are five to 

 seven narrow transverse vessels between the very much wider ones. The meshes 

 may extend the whole distance from fold to fold and then contain 20 to 24 stigmata, 

 or may be interrupted by irregular oblique or curved vessels (fig. 34). The stigmata 

 are rather short and neatly shaped. 



Dorsal Lamina a plain membrane. 



'Tentacles branched. There are 10 of large size, some rather larger than others, 

 and a few very small additional ones placed between. 



Dorsal Tvhercle having a symmetrical semicircular outline, with both ends lightly 

 rolled in (fig. 35). 



Locality : Tampalakam, Trincomalee. 



Cynthia transversaria, Sluiter, var. manaarensis, nov. Plate III., figs. 20 to 24. 



External Appearance. -Shape ovate or pyriform, with widely divergent prominent 

 apertures at the narrower anterior end (fig. 20). Attached by posterior half of left 

 side. Surface even, but closely encrusted with fine sand grains all over. Siphon 

 square in section, with slight ridges at the angles. Colour, greyish-yellow ; size, 

 3 centims. x 1"5 centims. x 1 centim. 



Test thin, but tough and stiffened by the embedded sand ; a little thickened at 

 posterior end ; dirty white on inside and in section. 



