32 BRITISH TUNICATA. 



fusiform : they are situated exactly in the same way as those 

 in the former species, but that on the right side is overlapped 

 liy the looped portion of the intestine. 



In an midescribed species [Molgula complanata, A. and H.] 

 obtained by the Eev. A. M. Norman in Guernsey, the genital 

 masses are ovate, and are placed as usual, but differ from 

 those of all other species in having' the oviducts passing from 

 their dorsal extremities, and consequently turned towards the 

 endostyle instead of being directed to the cloaca. The pro- 

 ducts of these organs are consequently thrown into the dorsal 

 portion of the atrium, far from the cloaca. 



There is only one reproductive mass in Euyijra nrenosa; it is 

 larger than usual, is of irregular form, and belongs to the 

 right side of the mantle, but overlies to a considerable extent 

 the alimentary tube. The oviduct, as usual, opens into the 

 cloaca ; but the rr/.s- deferens has not yet been observed, though 

 the male secreting-organ is distinctly visible, forming a con- 

 siderable part of the mass. 



In Clarelina lepadiformis, one of the Social Ascidiaus, the 

 genitalia are placed in the loop of the intestine near to the 

 lower extremity of the abdomen, the ovary lying on the right 

 of the alimentary tube, and the testis being spread over both 

 sides of it. The former resembles a bunch of grapes in which 

 the berries are of various sizes ; and the oviduct, like the stem 

 of the fruit, is seen in the midst of the ova ; and I believe I 

 have traced it passing up the abdomen in the direction of the 

 cloaca, but I did not succeed in determining' its outlet. M. 

 Milne-Edwards, in his well-known work on the ' Ascidies com- 

 posees,'* states that he could not discover how the eggs 

 passed from the ovary to the neighbourhood of the branchial 

 sac, and suggests the possibility of the vas deferens acting also 

 in the capacity of an oviduct. This, however, is exceedingly 

 improbable ; and, from what I have seen, there can be little 

 doubt of the presence of a true oviduct, although I do not 

 consider my observation a sufficient demonstration of the fact. 

 But there can be no mistake as to the existence of a /v/.s- 

 difcrens; this tube is sufficiently conspicuous; passing- up by 

 the side of the alimentary canal, it penetrates the lower 

 wall of the cloaca, and terminates by the side of the 

 anal outlet. The testis is a much-branched organ ; the 

 branches are extremely fine, and, dividing dichotomously, 

 terminate in numerous elongated fusiform vesicles, which are 

 united in pairs ; or, in other words, the ultimate twigs may be 



* ' Observations sur les Ascidies composees des cotes de la Mauclie/ p. 22. 



