On the Structure of a New Species of EartMvorm. 375 



part of the body, as in so many other earthworms. The 

 mesenteries forming the posterior boundary of segments, 

 6-12 inclusive — more especially the four anterior ones — are 

 stout and thick, and connected with each other and with the 

 body wall by tendinous threads. In front of the 6th segment 

 the mesenteries cease to be distinguishable as such, and their 

 place is occupied by a mass of fibres of varying thickness 

 and extent, which bind the alimentary canal to the parietes. 

 A dense mass of these is attached to the posterior half of the 

 pharynx, and serve, perhaps, as a retractor. 



Well developed segmental organs are found in all the 

 segments of the body, with the exception of the first one or 

 two. They exist in the segments which contain the sper- 

 mathecse and the prostates. As already mentioned, A. 

 kergueleuensis appears to be the only other species of the 

 genus which has segmental organs of the ordinary type. 



Circulatory System. — In segments 8-12 inclusive are a pair 

 of lateral hearts, which connect the ventral (supra nervian) 

 vascular trunk with a small and inconspicuous vessel which 

 runs along the upper surface of the alimentary canal beneath 

 the dorsal vessel. The last three pairs are the largest. It is 

 possible that, as in Pontodrilus, a communication also between 

 the lateral hearts and the dorsal vessel exists, but I could 

 not satisfy myself thoroughly as to its presence or absence, 

 but I am inclined to believe that it is absent. In each of 

 these segments there is also a largish blood vessel, which 

 arises behind the " heart," and apparently, together with it, 

 from the supra-intestinal trunk ; it supplies the mesentery 

 and ventral wall of the body. In the posterior region of the 

 body the dorsal vessel gives off three branches in each 

 seoment, two of which are distributed to the walls of the 

 intestine, while the third supplies the mesentery. Anteriorly 

 the dorsal vessel ramifies upon the surface of the gizzard. 



Genital System. — The testes consist apparently of three 

 pairs of racemose glands in segments 11, 12, and 13. This 

 description, however, applies only to one specimen; in all 

 the others that were dissected there was but a single pair of 

 testes fully developed, the rest being minute and rudimentary ; 

 the developed testes were those of the anterior pair. In the 



