378 Mr. H. D. S. Goodsir on some Gigantic Forms 



cavity which runs through the whole length of the body, but for 

 a considerable extent anteriorly is continuous and very much di- 

 lated ; in the remainder of its extent it is more confined and in- 

 terrupted by the ovaries which lie on each side of it. All that 

 portion of the body in which the common cavity is continuous 

 and dilated consists of one annulus, but the succeeding or ter- 

 minal is composed of a great many, each about the eighth of an 

 inch in length. Each of these separated annuli contains all the 

 elements of the perfect or original animal, viz. a male and female 

 generative apparatus, the cavity common to the generative, di 

 gestive and respiratory functions, and a small dorsal vessel ana- 

 logous to the intestinal canal of Nemertes. Serpentaria therefore 

 is a composite animal, each perfect individual consisting of nu- 

 merous and apparently still unformed or imperfectly formed in- 

 dividuals. That we are justified in looking upon this animal as 

 composite will be acknowledged from what will be stated still 

 further when referring to the physiological pheenomena it pre- 

 sents to us. 



When swimming this animal is very active, and advances with 

 considerable rapidity by means of an undulatory serpentine mo- 

 tion. "When handled it throws itself into various contortions, 

 and instantly casts off numerous annuli from the posterior part 

 of its body, each of which, immediately upon its separation from 

 the original, begins to move in a similar manner. The consist- 

 ence of the body when alive is soft and gelatinous, and is covered 

 with a thick tenacious slime. 



Nemertes. PI. XX. fig. 3. 



Gen. Char. — Anterior extremity of the body rounded, some- 

 what quadrilobate, with the proboscidean orifice in the centre. 

 Male generative apertures on each side. Cloaca or abdominal 

 surface immediately behind. Body cylindrical. The power of 

 division not great. 



Description. — The whole body of a dark umber colour with the 

 exception of a few narrow longitudinal white lines. The anterior 

 portion of the body is corrugated transversely. It is almost half 

 an inch in breadth, and tapers from this very gradually to the 

 terminal extremity. The anterior extremity is slightly quadrilo- 

 bate, and in the centre there is a small foramen through which a 

 long, narrow, extensile, trumpet-shaped proboscis can be pro- 

 truded at the will of the animal. On each side of this are two 

 narrow longitudinal slits similar to those in Serpentaria. The 

 edges however are more rounded, and consequently not so closely 

 applied to one another. These, as already mentioned, are aper- 

 tures to the male generative apparatus, which consists of two 

 long, narrow cellular tubes, running down each side of the body. 



