np:.mi:i!tixka iiayms. il'.', 



very expanded ediidition. Aiiollicr measures 52 rm.. and there are several nf 

 nearly this size. 



The colours of the large examples are no longer distinguishalile — some are 

 perfectly white, while others have apparently lieen discoloured liy the spirit in whirli 

 they were kept.* The young, however, still sliow the characteristic markings mentioned 

 in M'lntosh's description. The ground rnlonr is unw (in spirit) a dirtv I'eddish Im-dwh 

 above, somewhat jialer hclow. and with slight indications of a palci- longitudinal stripe 

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

 .streak passes dorsallv from near the hinder end of each slit, forming a nearK' c(ini]ilete 

 band across the head. 



In some of the large examples the liead is e.xceedinglv elongatt', the mouth 

 measuring 23 mm. (in the "Hut beach" specinu'u Ml) nun.) in length, and the 

 cephalic slits aliout (! mm. 



One specimen, measuring about 50 cm. in length, exhibits a verv marked 

 flattening of the posterior end. which led me to (juestion whethei' this was not of a 

 different species from the rest. It is, indeed, remarkably similar to the form des(;ribe(l 

 l)v Joubin (1908) as ( 'crehrdtnl ns i-linrcofi. By means of sections, however, I have 

 satisfied myself that there is no ground tor l)elie\ing that it is not an example of 

 A. ciirj-iufii/iis. It is a male, and in the flatteued posterior portion the testes mav be 

 seen in section, disposed peripherally within the muscles of the l)ody-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 l)e very weak. Hence the j^robable 

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

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

 ness, and less strongly muscular, in oi'der t(^ })rovide more I'oom for the sexual 

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

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

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

 remain so. 



I have been led. during my investigation of this spe(ies, 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 1 

 have had at mv disposal the tv[)es of the " C'liallenger." "" l)iscovcr\'. ' and '■ Southern 



* Tlie followiriff note on their colour,s durina; life has been submitted to mo by ]\Ir. D. G. Lillic : — 

 " The long Linrits-Yiki' specimens obtained in the Antarctic were of a imiplisli light red or terra-cotta 

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

 mucli alike in all the larger sjiecimens obtained.'' He adds, with regard to this .species, that " they liarl 

 great power of elongating and conti'acting their bodies." 



t The " Hut beach" specimen is fattened throughout its entire lengtli. hut it is prol)able that this 

 individual was in a moribund condition when collected, and f do )i()t attach any importance to its 

 e.vceptioiia! appeaiaiici'. 



U 2 



