NEMERTINEA P.AYLIS. !_':', 



very expanded cuiiilitioii. Another measures .V_> cm., and there aiv several of 

 nearlv tin's size. 



I he colours <>t flic large examples arc no longer distinguisliable sonic arc 

 perfectly white, while others have apparently lieen discoloiircil liy the spirit in which 

 they were kept.* The vomit;-, however, still show the characteristic markings inentioncd 

 in M'lntosh's description. The ground colour is now (in spirit) a dirtv reddish lirown 

 above, somewhat paler below, and with slight indications of a paler longitudinal stripe 

 on either side in some cases. The cephalic slits are edged with white, and a while 

 streak passes dorsally from near the hinder end of each slit, forming a nearlv complete 

 hand across the head. 



In some of the large examples the head is exceedingly elongate. I he nionlh 

 measuring '2-'< mm. (in the "Hut beach" specimen .".() mm.) in lenirili. and the 

 cephalic slits about (> mm. 



(>ne specimen, measuring aliont f>0 cm. in length, exhibits a vcrv marked 

 flattening of the posterior end. which led me to <|uestioii whether this was not of a 

 different species from the rest. It is, indeed, remarkably similar to the form described 

 hv Joubin (1!>OS) as Cerebratulus charcoti. By means of sections, however, 1 have 

 satisfied myself that there is no ground for believing that it is not an example of 

 /,. cun-iKjiitnx. It is a male, and in the flattened posterior portion the tesies mav be 

 seen in section, disposed peripherally within the muscles of the hodv-wall. The various 

 layers of the body-wall are much reduced in thickness in this region, and the muscle- 

 layers in particular appear at this point to be verv weak. Hence the probable 

 explanation of the flattening (which is seen in varying degrees in other specimens 

 alsof) is that at the time of sexual maturity the bodv-wall becomes reduced in thick- 

 ness, and less strongly muscular, in order to provide more room for the sexual 

 products which are ripening within. The natural result of this process would 

 be that the weakened portion would participate less fullv in the muscular contraction 

 which takes place under the action of a fixing reagent, and. if alreadv flattened, would 

 remain so. 



I have been led, during my investigation of this species, to entertain doubts as to 

 the validity of certain other species from Antarctic waters, and it is appropriate here 

 to make some reference to them. While working on the " Terra Nova " collection I 

 have had at my disposal the types of the " Challenger." " Discovery," and " Southern 



* The following note on their colours during life has been submitted to me by Mr. D. G. Lillie : 

 The long Xtneiu-like specimens obtained in the Antarctic were of a purplish light red or terra colt, -i 

 colour on the dorsal side, and a yellowish-creamy white on the under surface. The colouring was Y<TV 

 much alike in all the larger specimens obtained." He adrls, with regard to this species, that " they had 

 great power of elongating anil contracting their bodies.'' 



f The "Hut beach" specimen is flattened throughout its entire length, but it is prol>,-ible that this 

 individual was in a moribund condition when collected, and f do not. attach any importance to its 

 exceptional appearance. 



u 2 



