276 



Transactions of the Society. 



8. Lininodrilus i^ajpillosus sp. n. 



Length 25-50 mm. Segments 90 and upwards. A stout, 

 coarse worm, covered with small papillse. Opaque, somewhat 

 orange coloured, usually sluggish. Setse 5 in front, coarse, upper 

 tooth much larger than lower ; number decreasing in posterior seg- 



FiG. 43. 



ments. Pharynx in segments 2-3 ; chloragogen cells beginning in 

 6, brown. Ventral setfe wanting near male pores in adult. Front 

 segments annulate ; hearts in 8 and 9. Spermathecae striate, not 

 glandular, without a separate and distinct duct (fig. 43) ; no sper- 

 matophores seen. No penis-sheath has yet been discovered. 

 Brain rather deeply incised behind. 



This worm, like most others, 

 shows various modifications. In 

 Sussex I find it l^^ in. long, head 

 somewhat pointed, chloragogen cells 

 beginning in segment 6, though 5 is 

 the more usual position ; more setffi 

 (4-8) than in the type, and much 

 more tender and transparent. Again, 

 a Derbyshire form shows a sac where 

 the penis-sheath should be, and a 

 small chitinous process (fig. 44) which 

 might be a penial seta or a rudimen- 

 tary penis-sheath. I have studied Pig. 44. 

 specimens in all stages of develop- 

 ment, and regard the absence of the penis-sheath as supplying a 

 connecting link between this genus and those in which that organ 

 is normally wanting.* 



* N.B. — Pointner has found a fresh-water Annelid at Gratz which is destitute 

 of a penis-sheath. He therefore proposes to separate it from Lininodrilus and 

 call it Isochmta. His definition runs thus :— Dorsal setse the same as the ventral ; 

 hooked, but not pectinate. No capilliform setse. 



1. Penis destitute of chitinous sheath : Genus Isochieta. 



2. Penis with chitinous sheath : Genus Lininodrilus. 



One species only is described, and this very imperfectly, as follows : 

 Isochxta virulcnta, Pointner. — Habit of Lininodrilus : dorsal and ventral setse 

 of the same kind ; no penial setse. Segments 2-6 biannulate, larger anterior ring 

 carrying the setse. Ventral setse 4-8 per bundle in front, 2-3 in the middle, 

 gradually dying out. In the dorsal bundles 3-4 in front, in the middle and 

 posterior portions resembling the ventral. Teeth about equal in the middle and 

 hinder portions, in the anterior bundles the upper tooth is longer and smaller 

 than the under. The setse, spermathecse, and male apparatus are figured, but 

 nothing is said of the length, number of segments, or other particulars. It 

 seems, however, to be quite distinct from the species which are described in the 

 present paper. 



