DESCRIPTIONS OF GENERA AND SPECIES 335 



in other Enchytraeidae, and are not moved forwards as in Buchholzia appendiculata. 

 The setae of each bundle are of unequal sizes and are so arranged that the longest 

 setae of a ventral bundle come nearest to the longest setae of a lateral bundle. The 

 salivary glands are still more reduced than in the last species ; the median dorsal 

 diverticulum is only different from that of B. appendiculata in a few small points ; 

 it is not divided into two halves and the tubes are not so closely pressed together 

 as in the former species. The spermathecae are very unusual in the peculiar character 

 of the diverticulum ; this is a canal surrounding the end of the spermatheca a little 

 way off the end which opens into the oesophagus ; this canal communicates here and 

 there by pores with the main pouch. MICHAELSEN has also mentioned as existing 

 in the sixth or the seventh and eighth or in the ninth segment, unpaired papilla like 

 outgrowths of the epidermis which have the appearance of imperforate penes ; the 

 describer of the species thinks that these are not on account of their unpaired nature 

 to be looked upon as penes; otherwise, as he points out, we can more easily under- 

 stand the abnormal position of the reproductive organs in B. appendiculata. They 

 appear to me to be more comparable to the genital papillae so frequently met with 

 in the higher Oligochaeta. 



Genus ENCHYTRAEUS, HENLE. 



Syn. Neoenchytraeus, EISEN (in part.). 



Archienchytraeus, MICHAELSEN, ROSA (in part.). 

 Pachydrilus, TAUBER (in part.). 



DEFINITION. Setae of each bundle of equal length, straight, only hooked at free 

 extremity. Head-pore between prostomium and buccal segment. Oesophagus 

 passing gradually into intestine. Dorsal vessel arises behind clitellum. 



The principal character of this genus is in the shape of the setae. The other 

 characters are merely negative. It contains, according to MICHAELSEN, ten species, 

 which are reduced to nine by UDE, who unites E. humicultor with E. vejdovskii. 

 The species may be thus distinguished: 



I. Brain deeply cleft behind. 



i. Setae only one in each ' bundle ' E. monochaetus. 



ii. Setae more than one in each 'bundle': 



(1) Blood yellow E. arenarius. 



(2) Blood colourless . . E. spiculus. 



