416 



Mr. II. A. Bay lis on 



form a groove exteiulins; from tlie cloaca to tlie tip of tlie 

 tiiil. Some of the papillae are not infrequently carried over 

 80 as to lie on the inside of this groove, and are thus only 

 seen Avith some difficulty. In any case, however, the number 

 on eacdi side dot's not seem to he constant. 



The .';ame remarks apply, on the whole, to the material 

 from the South Shetlands, the infolding of the sides of the 

 tail (fig. 2 B) being often very marked. In this case the 

 largest numl)er of papillre counted was eleven on the right 

 side and eight on (lie h'ft. The tail is laterally compressed 

 in both fornis, and sligiitly asymmetrical, the right side 

 tending to be a Utile longer than tlie left. This is })robably 



■1''. 0. 



('. crassicuinhi ; views oftl.e caudal ends of two pairs of iudividiials, to 

 show tbe position during copulation. 



a peculiarity connected with (he mode of copulation, which is 

 Well seen in the material sent by Mr. Bennett. Several |.>airs 

 of individuals have remained, on fixation, in the position 

 indicated in fig. 5. The manner in which the tail of the 

 male is coiled round the constricted portion of the female is 

 apparently constant. The tail makes two or three tnins in 

 the direction of a right-handed scr< \v, but the last turn is 

 reversed, so that the tip of the tail comes to lie in front of, 

 instead of behind, the previous coil. This seems to ofi'er an 

 explanation of the slight asymmetry of the tail. 'J'lioii,i;h 

 Creplin noted the constriction in the region of the vulva, 

 and speculated as to the probability of its being a natural 



