Cha?topterus Variopedatus. 521 



opment, from those in which the notopodia and neuropodia ranged 

 from small papillae on the ventral side, to notopodia and neuropodia 

 of the usual form. In the earliest stage of its development a seg- 

 ment is indicated by a transverse row of four papillae on the ventral 

 side of the purse-like opening of the anus ; forward from these the 

 rows are progressively larger in size and more nearly like the full- 

 grown structures of the non-mutilated region. The notopodia develop 

 from the outer rows of papillae, the internal lobes of the neuropodia 

 from the middle pair of papillae, and the external lobes of the neuro- 

 podia appear, first in the second segment from the posterior end, as 

 small buds between the lateral and mesial rows just mentioned. The 

 gro\vth of these papillae is accompanied with a lateral displacement 

 so that the neuropodia finally occupy a position on the ventral side, 

 and the notopodia on the lateral side of the segments. The pair of 

 oldest notopodia of the regenerating segTiients, though considerably 

 smaller than those of the uninjured part, has the same shape and is 

 curved outAvard and backward in a horizontal plane that coincides 

 with that of the body. The second and third pairs are smaller ; 

 they diverge, first ventralwards then backwards. The fourth, fifth 

 and sixth pairs are still smallei'. They are nearly parallel conical 

 appendages on the ventral side, and between them are the small 

 neuropodia. Back of the sixth pairs they are progressively smaller 

 and lie wholly ventral in position. 



The formation of the parapodia is the same in uninjured speci- 

 mens, excepting that the contracted, or atrophied, '%old-fast" is 

 represented by a small papilla on the ventral side between the anus 

 and the youngest parapodial buds. The growing region is therefore 

 perianal in position. 



Digestive tract. — There has been a slight shifting and lengthening 

 of the muscular esophagus till it now opens into the dilated, green 

 stomach near the posterior margin of the plastron. Its walls are 

 ciliated throughout, from the broad buccal funnel anteriorly, to its 

 communication with the stomach. 



The stomach is a large thin-walled sac within the twelfth and 

 thirteenth segments, but which bulges forwards into the anterior 

 region and backward? into the first palette. Its walls have a darker 



