422 G. ^^^NHOFF. 



The point of greatest interest is the structure of the tail, which 

 differs widely from any structure of this kind yet described. The 

 epithelium has about the same height as in the body ; many gland 

 cells are present. I have not found any traces of the outer longitudinal 

 muscle layer. Circular and inner longitudinal muscle coat are present 

 as a single layer of muscle fibres. In the tail itself I have not been 

 able to trace the nervous system ; from the posterior commissure 

 of the body, however, nervous tissue is seen to reach the basis of the 

 tail. The centre of the tail is occupied by the intestine, which is 

 seen to communicate widely with the intestine of the body and opens 

 to the exterior by the anal aperture at the tip of the appendix. 

 There are no intestinal pouches, nor gonads nor rhynchocoelom in the 

 tail, which moreover lacks all connective tissue. Even the basement 

 membrane could not be distinguished. If any nervous tissue is present 

 it must be still epithelial. 



As to the vascular system, I have not been able to find the anal 

 anastomose nor anything like vessels in the appendix. 



Certainly there can be no doubt that this specimen belongs to the 

 sub-family Micrurinae. Had it not been for the tail, I should have 

 felt inclined to identify the fragment as Zineiis niveus, Punnett, which 

 lives at the much greater depth of 100-140 m. near Bergen in Norway. 

 As, however, Punnett describes the total absence of a tail in half a 

 dozen specimens he collected, and as I can only judge their relationship 

 by the hinder part of the body, I do not feel justified in considering 

 them identical. If my supposition is right, I am inclined to think 

 that a new genus ought to be created, on account of the structure of 

 the appendix and the very primitive features which Linens niveus 

 reveals. The presence of an appendix certainly would approximate 

 Lineus niveus still closer to Zygeupolia and Micrclla. 



Ordo II. ENOPLA. 



The body-wall consists of a single-layered epithelium, a basal mem- 

 brane, the outer circular and the inner longitudinal muscle layer. 

 Mouth anterior to the brain, or the oesophagus opens into the rhyn- 

 chodaeum. An oesophageal diverticulum is present. The nervous 

 system is not situated in the body-wall, but in the central connective 



SuBORDO A. PRORHYNCHOCOELOMIA. 



Worms with a very long and slender body ; they like to coil them- 

 selves up and to form knots. The proboscis is much shorter than the 

 body. The proboscis sheath never extends into the posterior third 



