214 OLIGOCHAETA 



into the canal a granular, glandular-looking mass is present (cf. with Naids and 

 Ilyodrilus). 



The regeneration of the tail has been studied principally by v. BtiLOW (1, 2) and Ran- 

 dolph (4). The principal point of interest in the actual process of regeneration concerns 

 the formation of the mesoblast. This appears to be produced by the division of large 

 peritoneal cells, which can be distinguished in the body-cavity of the adult worm ; 

 the name 'neoblasts' is suggested by Randolph for these cells. This process of 

 growth justifies a comparison between the regenerative process in this Annelid and 

 the 'budding' of Naids (see below). In the latter worms the budding zone begins 

 to be formed by a multiplication of peritoneal cells. The suggestion has been made 

 that these neoblasts correspond to ova which are also, of course, peritoneal cells. 



Vaillant (6) allows five species to this genus, viz. : — 



(1) Lunibriculus variegatus, Geube. 



(2) Lumbrieulus limosus, Leidy. 



(3) Lunibriculus spiralis, Leidy. 



(4) Lunibriculus hyalinus, Leidy. 



(5) Lumbrieulus lacustris, Czeeniavsky. 



The last, however, with a query, and justly ; for in the description given there is not a particle 

 of evidence that it is not, for example, a Clitellio. With regard to the two species, Lumbrieulus 

 spiralis and L. hyalinus (first of all placed by Leidy in a separate genus, Acestus), there is, again, not 

 the slightest evidence that they belong to this genus. The fact that there are from three to five or from 

 three to eight setae in each bundle argues rather that they are referable to some Tubificid like 

 Limnodrilus ; and that is the only possible character that can be drawn from the definition. 



Lumbrieulus limosus, on the other hand, appears at least a Lumbriculid, and it may be a Lum- 

 brieulus ; but the pores on the tenth segment suggest male pores, in which case it is not a Lumbrieulus. 

 Trhere are fifteen pairs of vascular caeca in each segment. 



Lumbrieulus variegatus, O. F. Mullee. 



Lumbrieulus variegatus, 0. F. MiJLiiEE, Verm, terrestr. vol. i. 3, 1774, p. 26. 

 Lumbrieulus teres, Dalyell, Powers of the Creator, vol. ii. 1853, p. 140. 

 Saenuris variegatus, Johnston, Cat. Worms, 1865, p. 6^. 



Deflnition. Length 80 mm.; number of segments, 300 y body dark green anteriorly ; 6-8 

 caecal appendages of dorsal vessel in each segment posteriorly. Hob. — Europe. 



This, the earliest known species of Lumbriculid, is much more imperfectly known 

 than most others ; the reproductive organs have not yet been properly described. 

 The species has been studied by d'Udekem (1, 5), Buchholtz, Ratzel (3), Vej- 

 DovsKr (24), BtJLOW (1, 2) and Randolph (4), in addition to the authorities 

 quoted above. Figures are given by Bonnet (PL i. figs. 1-5), Grxjbe (9, PI. vii. 



