REPORT ON THE TUNICATA. 179 



The intestine forms a wide loop. The yellow endocaxps are numerous, but rather 

 small. 



One specimen of this species was dredged at the Philippine Islands, at Station 208 ; 

 January 17, 1875 ; hit. 11° 37' N., long. 123° 32' E. ; depth, 18 fathoms ; bottom, mud. 



Polycarpa sulcata, Herdman (PI. XXIII. figs. 9-13). 



Polycarpa sulcata, Herdman, Prelim. Rep., Proc. Roy. Soc. Edin., 1880-81, p. 73. 



External Appearance. — The body is between ovate and pyramidal in shape, and is not 

 compressed. The anterior end is narrow, but rounded; the posterior end is broad and 

 rounded; the ventral edge is very convex, while the dorsal is convex posteriorly and 

 concave anteriorly. The body is attached by the posterior end of the ventral edge. The 

 branchial aperture is not terminal, but is twisted round to the dorsal edge; it is pro- 

 minent, and is directed dorsally. The atrial is on the dorsal edge, about half-way from 

 the anterior to the posterior end, and directed dorsally. Both are four-lobed, wide and 

 conspicuous. 



The surface is smooth but uneven ; it is cut up by deep creases and folds into 

 rounded pad-like projections. The colour is a dull creamy-white. 



Length of the body, 5 - 5 cm. ; breadth of the body, 3 - 5 cm. 



The Test is thick and tough, but soft and not stiff. The inner surface is white, with 

 small dark dots over it. 



The Mantle is thin, does not adhere to the test, and is of a dark brown colour; the 

 musculature is not strong. 



Tlie Branchial Sac has four narrow folds upon each side. Three narrow transverse 

 vessels are usually present between each pair of wider ones. The internal longitudinal 

 bars are few. The meshes are transversely elongated, and contain each about eight to 

 twelve stigmata. 



The Dorsal Lamina is smooth, and very narrow. 



The Tentacles consist of twelve rather large, but not very long, distantly placed ones, 

 with two or three very minute ones between each pair of the former. 



The Dorsal Tubercle is large and irregular, with a spongy appearance. 



This species has a very peculiar external appearance (IT. XXIII. figs. 9 and 10). The 

 anterior end appears to have been bent over, so that the branchial aperture comes to be 

 directed dorsally. Both apertures are wide and square. The test is thick and tough, but 

 lather soft, and is raised up on its external surface into a number of large rounded knobs 

 and ridges. In minute structure the test is composed of a finely and closely fibrillated 

 matrix, having somewhat the appearance of close felt (PI. XXIII. fig. 13, t.m.), and in 

 this are scattered here and there large hollow spaces or vessels containing Mood cor- 

 puscles. These form the small dark dots which are seen with the naked eye scattered 



(ZOOL. CHALL. EXP. PART XVII, — 1882.) K 24 



