4 W. F. T,AX('HKsTi:n. 



Further, on opeuiny up the Ixxly it is iouiul that llic \ciitral retractors arise 

 horn oiie-tliird to nearly one-half of the distance between the segmental openings 

 and the end of the body, which again suggcat^ Ph. fuscum ; Imt that the segmental 

 organs are very short and do not reach as far as tlie origin of the ventral 

 retractors, whicli accords with the arrangement in P/i. aiitarcticum. The latter 

 point is complicated liy the fact that in three of the specimens the segmental 

 organs do over-reach the ventral retractors l)y as far again, yet are not so much 

 as lialf the leniith of the bodv in Ph. fuscum. And tlu' number of coils of 

 the gut points to neither the one nor tlie other, as they vary from about fifteen to 

 about twenty-five (about eighteen in Ph. fuscum, about twenty in Ph. antarcticum). 

 'J'urning lastly to the papillae, we find that the description of them in the other two 

 species accords fully with their appearance in this, except that here they are variable in 

 one ])oint. Dr. Michaelson tells us that in Ph. (intarcticum they aiv '027 mm. wide 

 and 'OS nun. high [i.e. three times as high as wide) ; in Ph. fuscum, he only says that 

 they are "bis '07 mm. lang, also nicht ganz so laug wie die entsprechenden von 

 Ph. anfarcficinn," but the comparison of absolute lengths where the difterence is so 

 small is valueless, assuming the proportions to be the same ; so that we can only 

 coni-lude that they are practically identical in the two species of Michaelsen in regard 

 to this point. Now in our species tlie papillae in some individuals show this ratio of 

 ;l : I, but in others the ratio of the height is less (2"5 : 1, 2*25 : 1, 2 : 1). 



In Ph. f/eorgianum the introvert is only half the length of the l)ody, and the 

 papillae are much longer than in the other species quoted ; and these points, taken 

 along with other smaller diti'erences, seem to clearly separate our form from it. 

 From Ph. lagense Fischer, these specimens are very little distinct ; but this form is 

 itself hardiv to be distinguished from Ph. antarcticum. The thinness and clear 

 colouration seem to be the main distinction in most of the specimens ; and in all 

 of them the relative unimportance of the system of stria tion on the hind end. In 

 /*//. lar/i'Hsc, moreover, the segmental organs are as long as half the body. 



I su})join a list of measurements taken from a few of the specimens ; the 

 .sign " S.O." is meant to indicate the "opening of the segmental organ," and the 

 measurements are in millinu'tres and taken as accurately as the conditions would 

 permit. 



The letters A, 15, etc., correspond to dillcrcnt localities, while the figures 

 1, 2, .", etc., merely indicate difterent specimens. At the same time it mav be 

 pointed out that the \ anci B s])ecimens are all obviously of one type, viz., 

 thin-skinned and sti'aw-coloured, while those marked E and F are those that 1 

 have already mentioned as diti'ering from the rest in general facies, viz., dai'k in 

 colour and apparently thicker-skinnc(l. 



The most remarkalile dilference is to be found in the specimen marked E 2. 

 Here the extended introvert is much longer than the body, 26 • 3 mm. and 8 • 5 mm. 

 On the other hand, in the otic marked El, which presents all the general facies 



