igii.] 



J. Stephenson: Some Aquatic Oligochaeta. 



211 



The process of asexual division could be fairly well followed 

 from the preserved specimens. The value of n varies; 15, 17, 18, 

 20 and 21 were noted; in the budding zone are produced five 

 segments which will form the anterior end of B , and an indefinite 

 number forming the posterior part of A ; the proboscis of B 

 points backwards. The peculiarity of the process in these specimens 

 is the situation of the second and third budding zones : the 

 second zone of budding is established one original segment in 

 front of the first, i.e. . behind segment n — i ; and the third 

 appears again one segment in front of the second, behind segment 

 n — 2. The fourth appears in B, e.g., it may be behind original 

 segment xxxvi. (C/. Piguet, " Observations sur les Naididees," 

 Rev. Suisse de Zool., T. 14, 1906, p. 289.) 



Fig. 3.^ — Stylaria lacustns : a small part of the anterior region of the body, 

 including the base of the proboscis ; to show the shape of the cerebral ganglion ■ 

 X 210. Cii., cuticle; ep., epithelium; g,^ ganglion. 



Pristina proboscidea, Bedd., f. typica. 



With the preserved specimens of Stylaria lacustris, just des- 

 cribed, there occurred a single individual of the species' discussed 

 oy Michaelsen, Mem. Ind. Mus., vol. i, No. 3, p. 133^ under the 

 above designation. The specimens submitted to Michaelsen were 

 found living in Spongilla crassissima and 5. carteri, by Annandale 

 in Calcutta; the individual which I examined was taken with 

 the Stylaria from a pond in the Zoological Gardens and was 

 therefore living freely at the time of its capture. The specimen 

 agrees in most respects with what Michaelsen says ; a short note 

 will therefore be sufficient. 



The specimen was considerably curled; its length was esti- 

 mated at 5 mm. The ' proboscis ' was much shorter than in the 

 case of the specimens of Stylaria amongst which it was found 



