102 



BRITISH TUN1CATA. 



tubes, frequently united in pairs, pass upwards over 

 the surface of the ovigerous sac, and go to join, on the 

 median line, a slender vas deferens, which, passing 

 forward, terminates at the extremity of the oviduct. 

 There are thus as many oviducts and outlets for the 

 male secretion as there are compound reproductive 

 masses, and the eggs must be shed everywhere into 

 the atrial space between the branchial sac and the wall 

 of the pallia! chamber, and afterwards carried by the 

 atrial currents to the cloaca, whence they pass out as 

 usual by the excurrent tube. 



Besides the reproductive masses other very similarly- 

 formed bodies everywhere stud the mantle, and fill up 



FIG. 61. Ovaries of Styela tuberosa. More highly magnified. 



to a considerable extent the spaces between the former. 

 The latter bodies are most frequently pedunculate, and 

 are sometimes as large as the reproductive masses, 

 from which they chiefly differ in colour, being pale, some- 

 what pellucid, and almost homogeneous in structure. 

 They do not seem to have any high functional import, 

 their office apparently being to form, along with the 

 generative bodies, a sort of pad or level surface for the 

 support of the branchial sac, which otherwise might 

 suffer from the inequality produced by the genitalia. 

 These peculiar outgrowths are found in all the Ci/n- 

 t)i ithi' which have been examined. 



The reproductive organs are similar to the above in 

 S. mamiUaris and in some other species. 



