TWO NKW BRITISH NEMEETEANS. 657 



horizontal muscles above the mouth. The dorso-ventral 

 muscles are feebly developed. 



The proboscis sheath exteiids to within a millimetre of 

 the posterior end. It is composed of the usual outer circular 

 and inner longitudinal muscle layers. 



The proboscis is very stout and well developed. The 

 rhynchocoelomic epithelium which covers it externally (in the 

 retracted state) rests on a well-developed basement membrane 

 (fig. 14). This basement membrane is succeeded by an outer 

 longitudinal and a circular muscle layer, both of which are 

 very thin. Just inside the circular muscles is the nervous 

 layer, beneath which is the exceedingly thick inner longi- 

 tudinal muscle layer upon which rests the thin and almost 

 aglandular epithelium of the proboscis. 



As regards the alimentary canal, the mouth is behind 

 the brain and the anus terminal. Tn the oesophageal region 

 the epithelium contains but few glands. In the intestinal 

 region the epithelium is very granular. In the posterior part 

 of the intestine the epithelium is but slightly glanduhir, 

 whilst the intestinal diverticula become much shallower in 

 depth and less compressed. 



The vascular system in front of the brain shows wide 

 lacunae dorsal to the rhynchodseum as in the genus Eupolia. 

 These reach forwards in front of the proboscis pore (fig. 16). 

 The lateral vessels give off no diverticula embracing the cere- 

 bral organs (fig. 19, a — e, and fig. 22). There is a large 

 buccal commissure behind the commissure whence the median 

 dorsal vessel arises, but no buccal vessels arise from it. The 

 rest of the system is on the usual Heteronemertean plan. 

 The oesophageal lacunar network extends to the beginning of 

 the intestinal region. 



The excretory systeu) closely resembles that described 

 by Biirger (5, p. 181) for Eupolia. The tubules extend some 

 way dorsally and ventrally to the level of the side stems. 

 There are a number of ducts on either side (fig. 22), many 

 of which are incomplete, not piercing the circulnr muscle 

 layer. The number of ducts is not, however, so great as in 



