680 OLIGOCHAETA 



The prostomium is incomplete, extending over one-third of the buccal segment. The 

 setae are dorsal and ventral ; in the clitellar region they are longer and straighter, 

 but the modification appears to be not striking. The clitellum is variable in extent, 

 from 'six or seven to fourteen' segments; although on an inspection of the worm 

 this region of the body-wall does not seem to commence before the eighteenth segment, 

 in sections glandular cells are observable as far forward as the thirteenth segment. 

 This fact brings the relations of the worm to other Geoscolicidae much nearer than 

 might at first appeal-. In the neighbourhood of the clitellum are papillae having 

 much the same structure as those of Acanthodrilus georgianus (see p. 145) ; these, 

 too, vary in number and arrangement. They are however, as a rule, paired. In the 

 alimentary canal the describer of the species mentions the typhlosole as existing 

 only in segments xix, xx ; in addition to this ' singular longitudinal folds are to be 

 seen here at the ventral side of the intestine.' The sperm-sacs are present to the 

 number of four pairs in ix-xii. The number of pairs of spermathecae in each of 

 the segments where they occur varies from one to three ; in some cases, as in 

 Allolobophora complanata, the spermathecae lay in two segments. The spermathecae 

 were occasionally absent even in otherwise fully mature worms. In his more detailed 

 account of this species (17) HORST has illustrated its anatomy. 



Genus ANNADBILUS, HORST. 



DEFINITION. Setae strictly paired, not ornamented. Male pores on XXI/XXII. 

 Nephridia missing in first twelve segments. Spermathecae in XIV, XV, 

 XVI, more than one pair in each segment. 



This genus comes near to Glyphidrilus, but may be distinguished by a few 

 characters ; a further acquaintance with the two genera may lead to the fusion of 

 the two. In the meantime I follow HORST in allowing them to be distinct. The 

 main difference is in the absence in the present genus of spermiducal glands ; the 

 different position of the male pore I regard as of less importance. 



Annadrilus quadrangulus, HORST. 

 A. quadrangulus, HORST, Zool. Ergebn. Ost-Ind., ii, p. 44. 



Definition. Length, 50 mm. ; number of segments, about 200. Body rather quadrangular 

 posteriorly, with the setae implanted at the corners. Clitellum, XIX, XX XXV. Gizzard 

 in VIII. Sperm-sacs in IX-XII. Spermathecae, four pairs in XIV, jive pairs in XV, 

 and two pairs in XVI. Ilali. Sumatra, in Lake Danau di atas. 



