1906.] ASCIDIANS OF CAPE VERDE ISLAND. 909 



The test contains vascular bulbs, and rosette-shaped spicules- 

 are sparsely present. 



The branchial and atrial openings are not closely apposed and 

 are slit-like without lobes, both being present on the exposed 

 surface of the zooid. 



A well-developed branchial sac shows distinct longitudinal bars,, 

 straight stigmata, and a dorsal lamina with a plain membrane. 



The alimentary canal lies alongside the branchial sac. The 

 stomach is longitudinally ridged and has a csecum. 



The dorsal tubercle is oval. 



The tentacles are simple. 



In branchial stigmata, lamina, tentacles, tubercle, bars, &c., 

 these two specimens agree with Herdman's description. 



The apertures are distinctly slit-like and there is no suggestion 

 of lobes. 



Family Polyclinid.e Giard, 1872. 



Amaroucium crosslandii, sp. n. (Plate LXV. figs. 18-20.) 



The colony is fleshy and incrusting, and from its base of attach- 

 ment it grows up in an irregular convex manner towards the top. 

 The colour is a dirty yellow. The surface is smooth and glistening. 

 The length is about 6'5 cm. and breadth 4'6 cm. and thickness 

 •5 cm. 



The ascidiozooids are about 1*5 mm. long, are slender and club- 

 like, terminating posteriorly in a bluntly rounded end (fig. 18). 

 They lie at right angles to the surface of the test. Each is divided 

 into three regions — branchial, abdominal, and postabdominaJ, 

 The branchial aperture is terminal and 6-lobed ; the atrial, 

 which is situated dorsally, has a long languet. The zooids occupy 

 cavities in the test, which have each a separate opening to the 

 exterior. These openings occur in no definite arrangement. 

 The zooids in some instances were found extruded through these 

 apertures. The vipper part of the test is soft and fleshy and 

 surrounds the branchial and abdominal regions of the animal. 

 The lower part is tough, and in it is embedded the postabdominal 

 portion of the animal. The postabdomen is comparatively short. 



The test as already noted is firm and cartilaginous in the lower 

 part of the colony and soft and gelatinous in the upper part. It 

 is semitransparent and contains ver}^ few vessels. Terminal bulbs 

 are present. 



The mantle musculature, which forms an irregular network, is 

 well developed, particularly the longitudinal bands. 



The branchial-sac stigmata, in young specimens, are small, oval, 

 and fairly numerous (fig. 19), but longer slit-like stigmata are 

 present in older individuals. Numerous jDapillae project from the 

 sac into the branchial chamber. Longitudinal bars are absent. 



The endostyle is large and conspicuous and has a regularly 

 undulating course (fig. 20). 



Tlie dorsal lamina is formed of a laree number of closely 



