180 Transactions. 



transverse and longitudinal, I can find no difference from it except in the 

 chaetal formula. 



The chaetae are straight rods, arranged in a fan-shaped manner ; the 

 dorsal bundles contain usually 6 anteriorly to the clitellum, and 4-6 



posteriorly. The ventrals have 6 or 7 anteriorly, 

 and posteriorly may have but 4. though usually 

 the number is greater. The number in both 

 bundles occasionally drops to 3 in some of the 

 segments. The chaetae are not all alike in length, 

 those in the middle being shorter than those on 

 the outside. 



Fig. 7. — F. bollousi var. All the specimens collected by Captain Bollons 

 oliveri. A group of agreed in having, practically throughout the bodv, 

 lateral chaetae from the j 2 chaeta ftU tnege in Oliver's collection 



10th segment (camera) ; J . 



the tips are restored. have the above arrangement. Had 1 found the 



numbers mixed in the two lots, there would be 

 no doubt as to the validity of placing them in one and the same species ; 

 but I am faced with a doubt as to whether this marked difference in the 

 chaetal formula warrants one in forming even a new variety, for it does 

 not appear that any study has been made as to the extent to which 

 variation in this feature may go. Usually the number of chaetae forms 

 one of the diagnostic features ; but it seems to me preferable to make 

 this a variety under the circumstances of their collection. 



Fam. Tubificidae. 

 Rhizodrilus kermadecensis sp. no v. 



Four specimens were found in a " waterhole, on Meyer Island, 24/4/08." 

 They are a good deal curled and twisted, so that it is difficult to give actual 

 measurements, but approximately they Avould, I think, be about 40 mm. 

 in length. 



The prostomium is somewhat bluntly pointed — a rounded cone. 



The chaetae are all alike, bifurcated hooks 

 similar to those of Tubificids generally. The 

 upper or distal prong is longer and slenderer 

 than the lower prong, which is about twice its 

 thickness. 



In the dorsal bundle there are 5 or 6 in the 

 ante-clitellar segments and 2 in the rest of the 

 body. The ventral bundles contain 4-6 in the 



ante-clitellar segments and 3-2 posteriorly. _ ' D , , 



m , ,. ,, ° . r J . .. Iig. 8. — K. kermadecensis. 



1 he clitellum occupies segments £x, xi, xn, The free end of thechaeta. 

 and |xiii — that is to say, that in the case of the 

 first and last the glandular thickening ceases at the level of the chaetal ring. 



The male genital pore is median, in segment xi ; as is also that of the 

 spermatheca, in x. The pore in each case is longitudinal, with somewhat 

 overhanging lateral lips. These are especially noticeable in the case of 

 the male pore. 



The Male Apparatus (fig. 9). — The testes occupy the usual position. 



The sperm-funnel is very wide, flattened, and lies in the hinder wall of 

 segment x. From it issues the sperm-duct, which takes a nearly straight 

 course to the hinder end of segment xi. This first portion of the duct is 

 clothed with a continuous covering of tall club-shaped coelomic epithelial 



