114 R. C. PUNNETT. 



Two specimens were obtained measuring about 25 mm. in length and 5 mm. in breadth. 

 The specimens were not quite so flattened dorso-ventrally as most members of this genus, 

 owing to the fact that their bodies were bulged out by ripe gonads. The proboscis is 

 stout and measures about 10 mm. in length. The colour is a very pale pinkish-brown after 

 preservation, and no external markings are distinguishable. 



The epithelium is thick and rests upon a very thin basement membrane, which is not 

 nearly so sti'ong as the circular muscle layer just beneath it. The longitudinal muscle 

 layer is strong. 



The vascular system presents the usual metanemertean arrangement. 



The mouth opens just behind the proboscis pore, but the separation between the two 

 openings is complete. There is not even a depression into which both open as in most 

 species of the genus. In the cerebral region the greater part of the oesophagus (PL IV. 

 fig. 10) lies squeezed between the brain lobes. The blind gut extends about half-way from 

 its point of origin towards the brain. 



The proboscis sheath shews the usual basket-like arrangement of the muscle fibres. The 

 first few rhynchocoelomic diverticula are exceedingly small, and even in the posterior oeso- 

 phageal region they reach barely as far as the nervous stems. The proboscis shews the usual 

 structure. It contains but 14 nerves. 



The excretory tubules reach forward nearly as far as the opening of the cerebral organ. 

 The excretory pore (which is paired) is about the same distance behind the brain as the 

 front end of the brain is from the tip of the snout. It is ventral in position, and in 

 the specimen cut the duct is much reduced and was probably not functional. 



The gonidial sacs of the specimen cut contained large ripe ova. The sacs start in 

 the posterior oesophageal region, and then open just dorsal to the nervous stems on either 

 side. In the intestinal region the openings are ventral near the lateral edge of the body. 



The brain is very large, the dorsal ganglion being about 6 — 7 times the size of the 

 ventral (cf PI. IV. fig. 10). The two lobes of the brain are closely apposed, both dorsal and 

 ventral commissures being comparatively short. There is a small median dorsal nerve 

 between the basement membrane and circular muscle layer. The distance between the two 

 lateral stems in the intestinal and in the oesophageal regions is more than half the total 

 breadth of the body of the worm. There is a well-marked supra-anal nerve commissure. 



The cei'ebral organ is very large. It is situated entirely behind the brain. Its opening 

 is rather behind the level where it first appears m section'. It is lateral and slightly 

 ventral (cf PI. IV. fig. 11). The structure of the organ has already been described by 

 Burger in the paper referred to above. The essential peculiarity of the organ is the greatly 

 elongated glandular tube which stretches backwards above the nervous stems for a distance 

 which is rather more than double that of the organ itself The head furrows are well 

 marked and exteud round nearly two-thirds of the circumference of the head region. 



Large eyes are found, though the number of these is rather smaller than in most 

 species of the genus. About 26 in all are present. 



^ Burger gives a reconstruction of the organ [Zeit. fiir relation may be a local variation and does not appear suffi- 

 wiss. Zool. 1890, p. 240) from which it would appear that cient to separate the present form as a distinct species, 

 the organ is not placed entirely behind the brain. This 



