22 E - c - Punnett. [No. 2 



epithelium. The outer longitudinal muscle layer, is rather 

 more than double the thickness of the circular layer whilst this 

 in turn is considerably thicker than the inner longitudinal 

 layer. 



The proboscis is stout and both the two muscle layers are strong. 

 Well developed muscle crosses are present. The proboscis 

 sheath does not reach to the hind end of the body. 



The alimentary canal presents no features of special interest. 



In the vascular system a cephalic lacuna is present. 



The excretory system commences shortly after the posterior border 

 of the mouth and extends almost to the level where the 

 oesophagus joins the intestine. The tubules all lie dorsal to 

 the level of the nervous side stems. Dorsally they come into 

 close contact with the proboscis sheath. Four ducts are pre- 

 sent on one side and two on the other. They occur at irre- 

 gular intervals and are on the whole not nearer to the poste- 

 rior than to the auterior end of the excretory system (Pl. II, 

 fig. 17). 



The gonads are first found with the commencement of the intestine. 

 They alternate regularly with the intestinal pouches. 



Nervoas system. The dorsal ganglion is about half as large again 

 as the ventral. The dorsal lobe of the dorsal ganglion is 

 large. The cerebral organs are fairly well developed and, as 

 seen in section, are somewhat oval in shape, the longer dia- 

 meter being dorso-ventral. The head slits are fairly deep, 

 each slit being about 1 / 5 of the lateral diameter of the head 

 in the brain region. They extend backwards to the posterior 

 edge of the cerebral organ but are shallower after the ciliated 

 canal has been given off. 



Head glands, apart from the cutis glands, are absent. No 

 eyes. As the tip of the snout is somewhat damaged it is not 

 possible to state whether a frontal organ is present or not. 



13. Micrtwa bergenicola n. sp. 



Locolity. Radø fjord (near Bergen); from a depth of 10—25 

 metres of a mixed bottom of shell, mud and rock. A single 

 specimen only obtained. 



Externol features. The specimen was about 6 cm. in length with 

 a breadth of about 2 mm. Colour a uniform redbrown on 



