REPORT ON THE TUNICATA. 153 



sac, and runs vcntrally in an undulating course (PL XI. fig. 2) to open into the 

 anterior end of the stomaeli. The intestine, on emerging from the posterior end 

 of the stomach, runs dorsally and posteriorly, also in an undulating course, to 

 terminate near the posterior end of the body. The duct from the reproductive organs 

 runs near the oesophagus to open into the peribranchial cavity close to the base of the 

 atrial siphon. The arrangement of the viscera agrees with that oi Abyssascidia ivyvillii 

 except that in that species they were placed upon the right side of the branchial sac. 

 The arrangement of the alimentary canal, the relative positions of oesophagus and 

 intestine, and the relations to the reproductive mass, are the same in the two eases. 



The chief points in which the present species does not agree with the genus 

 Ahyssascidia as defined in the first part of this Report, are the number of lobes around 

 the branchial and atrial apertures, and the relations of the branchial sac and viscera. 

 This is a right-handed species, while Ahyssascidia ivyvillii is a left-handed species ; but 

 as both are represented by single specimens only, too much stress must not be put upon 

 this difierence, as one of them may possibly be a reversed individual. Left-handed 

 specimens of Asoidia are sometimes found. Consequently I shall not modify the 

 characters of Ahyssascidia yet. Some other specimens may be found which will enable 

 us to decide which condition is the normal one in the genus, and whether or not the 

 present species belongs to Ahyssascidia, or requires to be separated as the type of a 

 new genus. 



Styela sericata, u, sp, (PI. XL figs, 14-16), 



External Appearance. — The body is of an elongated ellipsoidal form, with the 

 anterior end slightly narrower than the posterior, and with the sides nearly equally 

 convex. The body is apparently not attached. The apertures are sessile, fourdobed, 

 and placed far apart. The branchial is anterior and terminal, while the atrial is 

 placed on the dorsal surface fully three^fourths of the way to the posterior end of 

 the body. The surface of the test is even, Init is covered with long delicate silky 

 processes which form a hairy investment, to which a few sand grains adhere. The 

 colour is yellowish grey. 



Length nearly 3 cm. ; breadth, at middle of body, 1 '3 em, 



T/ie Test is thin but tough and leathery. Its inner surface is smooth and of a 

 whitish colour. The outer surface is minutely roughened, and is covered with delicate 

 hair-like processes of various lengths. 



The Mantle is thin and adheres closely to the test. The musculature is delicate 

 but close. The muscle bundles run in all directions. 



T7ie Branchicd Sac is large and well developed. The folds are slight, being 

 merely produced by the approximation of a number of internal longitudinal bars. 

 There are eight or ten bars in such places. The meshes in the opener parts of the 



(ZOOL. CHALL. EXP. — PART LXXVI. 1888.) Gggg 20 



