8 THE ANATOMY AND DEVELOPMENT OF PERIPATUS NOVAE- BRITANNIAE. 



Thus the absence of crural glands and of white papillae on the legs of the male 

 of P. novae-britanniae is a feature in which this species resembles P. novae-zealandiae. 



vi. Feet. The variability of the primary papillae which occur on the feet is 

 another interesting peculiarity of the New Britain Peripatus. In all species except 

 P. sumatranus, there are three papillae in the immediate neighbourhood of the claws 

 on each foot. In the African and Neotropical species one of these papillae occurs on 

 the hinder margin of the foot, and the other two papillae lie close together at the 

 anterior margin of the foot. In the Australasian Peripatus there is a primary papilla 

 at the anterior and posterior margins, while the third papilla has a median dorsal 

 position. In P. sumatranus, as described by Horst, there are only two papillae on the 

 foot at its anterior and posterior margins respectively. Sedgwick (19) states that the 

 condition last described is, if true, unique in his experience of Peripatus 1 . 



In the Peripatus of New Britain the foot is duly provided with three papillae, 

 two of which constantly occur in the usual marginal positions, but the third papilla 

 may be median dorsal or it may be slightly excentric, or again it may be approximated 

 to the anterior papilla (Figs. 8 a and b). The variation occurs in the feet of individual 

 specimens. In the greater number of cases, so far as I have observed, the dorsal 

 papilla is not median but sub-median or sub-anterior. Thus in one specimen (X) I 

 found that the dorsal papilla was generally sub-median, but sometimes median. In 

 another (XI) on the right side it was median in 10 feet and not median in 13 (in 

 one foot its position appeared doubtful), while on the left side of the same individual 

 it was median in 6 feet and not median in 18. In this specimen, to take a concrete 

 example, the dorsal papilla of the 16th foot of the right side was markedly excentric 

 (Fig. 8 a), while that of the corresponding foot of the left side was accurately median. 



The primary papillae in our species are simple conical structures without a con- 

 striction separating the distal spine-bearing portion from the rest of the papilla. 



INTERNAL ANATOMY. 



The several subgenera of Peripatus differ from one another very considerably in 

 the constitution of the reproductive organs. Otherwise the main features of their 

 organisation are fairly uniform although it is probable that a detailed investigation of 

 their finer anatomy would reveal certain contrasts among themselves. 



Segmental Organs. 



It has been mentioned above that when the segmental organ belonging to the 

 segment which carries the 6th pair of legs opens distally by a pore situated in the 

 centre of the 3rd spinous pad, the organ itself is not specially enlarged as are those 

 of the 4th and 5th legs, but resembles a normal nephridium. 



Here, as in other species of Peripatus, a typical nephridium consists of four principal 

 portions, viz. (1) an outer dilated vesicle or bladder, (2) a coiled portion recurved 

 upon itself so that (3) the thick-walled funnel lies approximately in the same transverse 



1 The third papilla is not figured by Gaffron in the feet of P. trinidaderisis ( = edwardsii partim). 



