STYELA TUBEKOSA. 103 



Several interesting modifications of these organs are 

 found in various species. In 8. variabilis the ovaries 

 assume the form of distinct, wide, slightly undulated 

 tubes, of which there are two on the right and two on 

 the left side of the mantle, each having its own short, 

 nipple-like oviduct which opens into the cloaca, there 

 beine: two on either side of the anus. The testis is 



o 



composed of numerous, irregular ly-lobulated vesicles 

 scattered over the lower portion of the mantle on both 

 sides, in the vicinity of the posterior extremities of the 

 ovaries, but with which they have no connection, each 

 separate vesicle having its own short, papillose vas 

 deferens. 



In the interstices amidst the reproductive nodules 

 are numerous, soft, pallial nodules which vary much 

 in size and form; but are usually more or less rounded, 

 and rarely so large as the former. 



1. Styela tuberosa (Macgillivray). 



(PI. XXXIV, figs. 1-5; PI. XXXV, fig. 1; PI. XXXVI, 



figs. 1-7; PI. XLVIII, fig. 9; and figs. 60 

 and 61 in text.) 



Cynthia tuberosa MACGILLIVRAY Moll. Anim. Aberdeen 

 [1843], p. 311 ; FOKBES & HANLEY Brit. Moll. I [1848], 

 p. 37 ALDER & HANCOCK in Trans. Tyneside Nat. Field 

 Club, I [1848], p. 195; [ANSTED & LATHAM Channel Isl. 

 (1862), p. 219; ALDER in Rep. Brit. Assoc. for 186(3 

 (1867), p. 208; M. & G-. 0. SARS Christianiafjord. Fauna, 

 pt. 2 (1870), p. 102]. 



Body irregularly conical or sub-tuberous, pale brown, 

 with a tinge of red towards the apertures, broadly 

 attached at the base by root-like prolongations of the 

 test. Apertures, branchial terminal, tubular, and 

 broadly conical, uniting in outline with the body ; 

 atrial situated on a prominent subquadrate tube, rather 

 more than a third down the side ; both apertures 

 reddish, and streaked internally with rose-colour and 

 white. Test (PI. XXXIV, figs. 1 and 5) thick, tough, 



