TUNICATA. 317 



Branchial Sac with four wide folds on each side. There are five internal bars on a 

 fold and three rows of meshes in the interspace. The transverse vessels are of three 

 orders. The meshes arc elongated transversely and contain eight or nine stigmata, 

 and may be crossed by a narrow horizontal membrane (fig. 33). 



Tentacles simple, numerous, large and small alternately. 



Dorsal Lamina a plain membrane. 



Dorsal Tubercle having a simple rather angular horse-shoe curve with a wide 

 opening. The ends turn slightly either in or out (figs. 31 and 32). 



Alimentary Canal large, stomach ridged longitudinally, intestine wide, forming a 

 close loop. 



Gonads four to six on the right side, one or two on the left (figs. 27 to 30). 



Localities: (1) Arijm coral reef, four specimens; (2) Station LIIL, 10 miles 

 north of Cheval Paar, 7 to 8 fathoms, four specimens; (3) Station I., oft' Negombo, 

 12 to 20 fathoms, four specimens (one of these is almost bare of sand and another is 

 more than half covered with reddish brown large sand grains so as to closely resemble 

 in appearance the sandy Rhabdocynthia, Rk. ceylonica, found in the same neighbour- 

 hood) ; (4) Station X., East of Cheval Paar, 6 fathoms, three specimens one large 

 (fig. 26) with half a dozen young pearl oysters adhering, almost free from sand, test 

 milk-white and corrugated at anterior end", one smaller half-covered, and one wholly 

 covered with red-brown sand except the two siphons and a strong ridge of test 

 connecting them ; (5) Station LIV., North end of Gulf of Manaar, half a dozen small 

 specimens from 1 centim. to 2 - 5 centims. in length ; (6) Station XLIX., South end ot 

 Periya Paar, 13 fathoms., one specimen. 



Although Heller's description is very brief, the name he gives the species 

 inappropriate, and his single figure of the external appearance not characteristic, still 

 I have no doubt that his specimen, brought from Ceylon by Schmarda, belonged to 

 the same species as those I have now before me. The milk-white colour and the long 

 tubular gonads, about four on the right side and two on the left, are characteristic 

 features mentioned by Heller which render the identification fairly certain. He 

 does not mention the sand which is usually present on the surface, and the areolation 

 of which he makes so much is by no means always present. However, feeling 

 confident that it is the same species that is in question, I have re-described and 

 figured Heller's S. areolata from the specimens in the present collection. 



The few prominent tubular gonads on each side of the body in this species recall 

 the arrangement seen in Sluiter's eastern species Styela oliaoearpa and Styela 

 sedata ; but in other points of structure and in external appearance the Ceylon 

 specimen differs from both of these, although they must be regarded as allied forms. 



Styela ascidioides, n. sp. Plate V., figs. 27 to 32. 



External Appearance. Body oblong, erect, attached by a short narrow stalk or 

 posterior thickening. Branchial aperture on anterior end, atrial on dorsal edge, one- 



