ON SOME SOUTH PACrFIC NEMERTINES COLLECTED BY DR WILLEY. 575 



muscle layer they stretch tar past the brain into the mid-gut region. Some idea of 

 their extent may be gathered when it is stated that in the series of sections through 

 the animal the brain occupies sections 90 — 135 whilst the head glands reach to 

 section 2G0. They are rendered exceedingly conspicuous by thidiiin in which they 

 take a deep reddish purple tinge (Figs. 2.S and 29). 



The head slits are deep and ventral in position reaching from the anterior end 

 to a short distance behind the spot where the cerebi'al canal opens into them 

 (Fig. 28). 



The dorsal ganglion passes insensibly into the cerebral organ, the glandular 

 layer of which lies quite internal (Fig. 30). Inside this glandular portion were a 

 number of small circular bright green bodies containing in the centre a well stained 

 nucleus. Their brilliant colour renders them exceedingly conspicuous but I am unable 

 to make any suggestion as to their nature. In appearance they bear some resemblance 

 to unicellular algae. Moreover many of them are clustered together suggesting that 

 some process of division had been going on (Fig. 30 *j. The nerve cords form no 

 commissure by the anus. 



The circular head furrow so characteristic of the genns appears to be absent. 



The excretory system is continuous and opens by several ducts on each side, 

 though these are fewer in number than in E. multiporata. The ducts pass as usual 

 just over the dorsal side of the lateral nerve cord.s. 



About the vascular system nothing definite can be said as the state of con- 

 traction rendered it impossible to observe with any certainty the course of the vessels 

 from section to section. No eyes are present. 



5. Eupolia heinprichi (Ehrenbekg, 1831). PI. LX. Fig. 32. 



A single specimen from sand in rock pools at Lifu. With regard to its markings 

 the animal shews a slight divergence from that described by Burger (1) page 22 

 (under the name of E. brockii) in that the brown transverse line near the anterior 

 extremity is not continued ventrally to form a complete ring. Also the ventral brown 

 line commences further back and soon becomes indistinct. The length of the animal 

 in life was over 30 cm., its breadth being about 3 mm. of which 1 mm. was taken 

 up by the dorsal longitudinal stripe. A figure of the animal is given in the paper 

 cited above, Taf I. fig. 10. 



With regard to its inner organisation it agrees with Btirger's account. Although 

 I have a complete series of sections through the anterior portion of the animal 

 I have been unable to find the openings of the excretory system which in this genus 

 are generally so well marked as they traverse the thick gelatinous layer of the cutis. 

 An interesting point is the presence of large cells resembling ova scattered about 

 and lying as far forwards as the level of the cerebral organ (Fig. 32, ov.). As each 

 is surrounded b}' a fine epithelium with fiattened nuclei, and lies in a cavity lined 

 by a similar epithelium, it seems more natural to regard them as ova than as parasitic 

 Gregarines. Unfortunately the animal contained no undoubted ova with which to 

 compare them. 



