80 THE FISSIGEMMATION OF 



closely allied animals presents one of the resultants in such a 

 form, that, were it the product of the only known instance of 

 self-division, it would be set down, without hesitation, as simply 

 the reproductive organ removed from the body of a perfect in- 

 dividual. The latter is the Tape-worm, of which there are a great 

 number of species living in, and undergoing this process in the 

 intestines of all sorts of animals, and the former is one of the 

 marine worms, of which, as well as of the fresh-water kinds, 

 many have been found to undergo self-division. 



The most remarkable 

 example known among 

 the aquatic worms is rep- 

 resented here (fig. 43), 

 under the name of My- 

 rianida fasciata, as the 

 species was originally call- 

 ed by its discoverer.* The 

 oar-like appendages which 

 are attached to the rings 

 of the body are devoted 

 not only to the office of 

 propulsion, but also, re- 

 ceiving branches from the 

 blood-vessels of the body, 

 serve the function of gills, 

 or breathing organs. The 



Fig. 43. mouth is at the broader 



end, and from that the intestine extends in a direct course to the 

 extreme posterior end of the body. About the intestine there are 

 several blood-vessels which cover it with a sort of net-work, and, 

 as mentioned just now, are connected with each of the branch- 

 Fig. 43. Myrianida fasciata. M. Edw. 2 diam. A marine worm, under- 

 going multiplication by transverse self-division. //, the head ; 1, 2, 3, 4,5,6, 

 the successively more advanced individuals, 1 being the oldest and 6 the young- 

 est. From Milne Edwards. 



* Milne Edwards, Voyage en Sicile, vol. I. p. 43, pi. vn. fig. 65. 



