Kdrdiicoi'in fruin Kcuwlor. 243 



which presents this peculiarity, that its line of origin takes a 

 spiral course round the wall of the gut ; so that we have, in 

 j)lace of the straight valve commonly found in earthworms, a 

 si)iral valve. 



Tiie vascular si/stem presents the characteristic '^ intestinal 

 liearts " which Perrier was the first to describe, and which 

 are now known in other genera than Rhinodrilus] there are 

 two pairs only of these commissural vessels in the present 

 species, greatly dilated and communicating not with the 

 dorsal, but with the " supra-intestinal " vessel, as Mr. Bed- 

 dard has figured for his species ; they belong to somites xi. and 

 xii., though tiiey appear to lie in somites xiii, and xiv., the 

 first passing between the second and third intestinal diver- 

 ticula and the second heart between the third and fourth of 

 these. 



Immediately in front of these " intestinal hearts " (fig. 3, 

 ih.) are three j)airs of very much smaller "lateral hearts" 

 {l.h.) arising from the dorsal vessel ; these tiiree lie close 

 behind one another between the gizzard and the first diver- 

 ticulum. It is a matter of some uncertainty whether these 

 lie in somites viii.,ix.,x., or in vii., viii., ix. The dorsal vessel 

 {d.v.) isampullated in somitexv. and ineachsomite posteriorly, 

 where it lies above the sacculated intestine ; but anteriorly 

 to this, in the region of the " intestinal hearts" and intestinal 

 diverticula, it is practically cylindrical, though it gradually 

 diminishes in size, and where tlie " lateral hearts " leave it 

 it has become quite narrow. The dorsal vessel appears to 

 terminate behind the gizzard, for I could see no median vessel 

 beyond this point; Mr. Beddard states {loc. cit. p. loS) that 

 anteriorly to the gizzard the " dorsal vessel runs some way 

 above the surface of the oesophagus ; " so that it is possible 

 that I had removed it in this region, though it seemed to end 

 quite definitely behind ilie gizzard. 



In B. Guliehnus there are three pairs of " intestinal hearts " 

 in somites x., xi., xii., the hindermost pair of which is 

 smaller and not dilated ; in front of these there are two pairs 

 of narrow '' lateral hearts." 



In R. Tenhatei there are also two pairs of lateral hearts, 

 which, according to Horst, lie in somites xii. and xiii,, and 

 behind these are two pairs of " intestinal hearts," passing 

 between the first and second and between the second and 

 third intestinal diverticula. 



With regard to R. paradoxus^ the " intestinal hearts " are 

 stated to lie in somites xx., xxi., and xxii., though whether 

 this apparent position is due to displacement or not can 

 only be settled by a renewed examination of the species; it 



