134 VERANY AND VOGT ON THE HECTOCOTYLt 



which especially invest the aortic heart and the great vessels 

 uniting the latter with the branchiae. Below this mass of venous 

 appendages we see a flask-shaped organ of a gelatinous trans- 

 parency, and through which fine silvery lines may be distin- 

 guished ; these have a very peculiar lustre, and look like white 

 lights painted thickly and with great brilliancy upon a grayish 

 satin ground. These lines differ much in their arrangement in 

 different specimens ; we see, however, that they are especially 

 numerous towards the posterior convex edge of the flask, whilst 

 the anterior hollowed border of this organ seems to contain a 

 more transparent substance. The bottom of the flask, whose 

 form varies very much in consequence of the great contractility 

 which it possesses, is turned to the right, while its narrowed 

 neck passes to the left upon the great vessels of the branchia. 

 This extremity hooks round these vessels, and at the summit of 

 the curve is found the cleft orifice of which we have spoken 

 above. 



The remainder of the generative apparatus (PL II. fig. 4.) is 

 situated upon the dorsal surface of the intestinal sac, and is con- 

 tinuous with the neck of the flask. It is composed of an elongated 

 vesicle having nearly the same form as the flask, and possessing 

 as great contractility in its transparent muscular parietes. It 

 is divided into two portions, which however are united in a 

 common envelope. The anterior portion we will call the cornu : 

 it is membranous and transparent, and allows a contained 

 whitish spiral thread to be seen through its side, much less 

 brilliant and larger than the threads contained in the flask. At 

 the posterior enlarged extremity of the cornu there is attached 

 an organ having the form of a pointed apple, whose base is 

 turned towards the cornu, its point towards the right branchia, 

 with the heart corresponding to which it is in contact. This 

 organ has a yellowish chalky tint ; its internal surface is strongly 

 attached by cellular tissue to the base of the flask ; it is the 

 testicle. The generative organs thus form altogether an actual 

 ring (PL II. fig. 3.) round the great vessels of the left branchia ; a 

 ring which is completed behind only by the fibrous tissue uniting 

 the envelope of the testicle to the bottom of the flask, whilst the 

 closure of the ring in front, upon the ventral face, is produced 

 by the union of the neck of the flask with the neck of the cornu. 



