566 WILLIAM BLAXLAND BENHAM. 



The absence of a gizzard, both in Criodrilus and in Ponto- 

 drilus, is probably related to the soft nature of their food- 

 material. Both are aquatic in habit. Pontodrilus, as 

 Perrier tells us, lives on the seashore, and its food consists of 

 decaying vegetable matter thrown up by the sea. Criodrilus 

 lives entirely in the water, and obtains its food, according to 

 Orley, by swallowing the mud which contains decomposing 

 vegetable matter. In both cases the food is soft, and already 

 more or less finely divided, and can be easily digested, so that 

 the necessity for a gizzard does not exist : in Lumbricus and 

 other worms, however, which live on land and burrow and 

 swallow the hard soil, some crushing apparatus is needed before 

 the digestive fluid secreted by the wall of the intestine can act 

 on the food. 



The vascular system I have not traced to any extent. 

 The dorsal blood-trunk is large, and has the usual ampullate 

 appearance up to somite xv. In the next preceding somite it 

 is bent slightly to one side, and gradually gets narrower till it 

 divides up on the wall of the pharynx. In each of the somites 

 VII to XI a pair of large and long moniliform hearts unite the 

 dorsal to the ventral trunk ; and there are lateral vessels in 

 each of the somites posterior to the hearts. 



In the neighbourhood of the anus the dorsal trunk divides 

 into two (Vejdovsky ; pi. xiv). A subneural vessel is present 

 and a typhi osolar vessel, but neither latero-neural nor intes- 

 tino-tegumentary vessels exist. 



The nervous system presents no points of difference from 

 the usual arrangement. The three '^ great fibres" are present. 



The nephridia are not present in front of somite xiii. 

 A series of sections confirmed the results derived from 

 dissection. In and behind this somite they are large and 

 fairly conspicuous organs, having a slight muscular vesi- 

 cular portion. Vejdovsky states that they open exteriorly 

 in front of the ventral setse : he also figures a nephridial 

 funnel (pi. xiii, 21), which somewhat resembles that of 

 Lumbricus. 



Pontodrilus agrees with Criodrilus in that there are no 



