SOME ASCIDIANS FROM THE ISLE OF WIGHT. 139 



Form (3. — Depressa. Attached as described above ; littoral. 



Clmunel Isles (= ^. ruhrotincta and A, robusta, 

 Hancock). 

 Var. 3. — Rata. Body-walls yellowish, with little or uo trace of red ; tentacles 

 rarely exceediug 40 in number. 



Form a. — Erecta. As above ; infra-littoral. 



Adriatic. [West coast of Scotland (= A. lata, 

 Hei'dman ; but the colour of this race is only known 

 from spirit specimens).] 

 Form /3. — Depressa. As above ; littoral. 

 Isle of Wiffht. 



DESCRIPTION OF PLATES VI and YII, 



Illustrating Mr. W. Garstang's paper '^ On some Ascidians from 

 the Isle of Wight." 



N.B. — All the figures were drawn from preserved material. 



PLATE VI. 



Fig. 1. — Ascidia mollis, Aid. and Hauc. The largest normal individual, nat. size. 



Fig. 2. — A, mollis. Culs-de-sac of the test-vessels, magnified. 



Fig. 3. — A. mollis. Another individual of smaller size, as seen after removal of the 

 test ; twice the natural size. 



a. = View of the right side, showing the musculature. 



5. = View of the left side, showing the disposition of stomach and intestine. 



Fig. 4. — A. mollis. Portion of the pharyngeal wall of the same individual ; much 

 enlarged. Zeiss, Obj. A. Oc. 2, Cam. luc. The dark portions represent the longitudinal 

 furrows, the light portions the elevations which are caused by the " minute plication " of 

 the wall. 



c.(/. = Connecting ducts between the horizontal and the internal longitudinal vessels. 

 A.«. = Horizontal vessels, forming three complete series and a rudimentary fourth. 

 V.?.6. = Internal longitudinal bars or vessels. 

 i.^.= Intermediate papillse. 

 iJ. = Papill2B on the int. long, bars above the connecting ducts. 



Fig. 5. — A. mollis. The large abnormal individual, nat. size. 



a. = View from above the dorsal surface. The left side consists entirely of the area 

 of attachment ; the right side forms an elevated ridge. The inconspicuous 

 slit-like oral and cloacal apertures are indicated. 

 J. = View of the opposite surface. 



