NEMERTEANS 237 



marked upon by Burger (1895, p. 547), appears in these Saldanha Bay forms. The chief 

 difference lies in the uniform rose red or carmine tint of E. antonina, which is considered 

 characteristic of the species by Hubrecht (1879, p. 231). The colour is noted also by 

 Joubin (1894, p. 206). The body of E. antonina appears to be considerably more slender 

 than this South African worm, and the main stylet in the armature of the latter does not 

 bear the proportion 3 : 1 to its base, although it is certainly longer than the base in the 

 specimens I have examined. Taking these facts into consideration I do not consider the 

 identification of these worms with E. antonina is justified, but there seem to be good 

 grounds for considering that the same forms were described by Schmarda under the 

 specific name ophiocephala. 



Genus Nemertopsis, Burger 



Nemertopsis tenuis, Burger, 1895 (Plate XV, fig. 7). 



Eight specimens were found at different dates in attached kelp roots from the granite 

 boulders between tide-marks on the outer coast. The lengths ranged from 10 to 41 mm., 

 the corresponding breadths being 0-3 and 0-4-0-5 mm. 



Form and colour in life. The body is very thin, almost Nematode-like. The head is not 

 distinct from the body, and the tail tapers acutely. The four small eyes occur in close-set 

 pairs, the posterior pair being very far behind the anterior. The colour is yellowish 

 brown and the gut shows pale through the skin. Yellow-red blood vessels, especially the 

 dorsal vessel in the posterior half of the body, are evident in some specimens. 



Form and colour of preserved specimens. Considerable shrinkage takes place after 

 preservation. The colour is bleached. On clearing in anilin oil the brown cup-like eyes 

 can be faintly seen. 



Internal structure. The oesophagus opens into the rhynchodaeum just posterior to 

 the cerebral organs and in front of the brain. The contents of the cells of the stomach 

 wall stain deeply with haematoxylin. The anterior caecum has no forward branches. 



The epithelium is as thick as the longitudinal muscle layer, and the basement mem- 

 brane is about half as thick as the circular muscle layer. The longitudinal muscles are 

 not conspicuously divided into bundles. A compact head gland is present, opening 

 dorsally just above the proboscis pore. The head gland reaches the brain. 



The rhynchocoel extends about one-third of the body length. The proboscis has ten 

 nerves. The armature is not known. 



There are two definite blood vessels in the head forming a loop beneath the head 

 gland. At the ganglia these vessels become difficult to trace, but posterior to the ex- 

 cretory tubules there are two vessels lateral to the rhynchocoel and a median vessel 

 above the gut. This median vessel is formed originally of branches from the laterals. 



The convoluted excretory tubule is packed closely behind the dorsal ganglion and 

 opens to the exterior by a single duct above the lateral nerve. 



The brain is not peculiar. The ventral commissure is thicker than the dorsal, and the 

 lateral nerves leave the brain sharply and turn back as sharply after undergoing a knot- 



