^4 Olive B. Davtes: 



■contact. In Figs. xi. and xiv. it seems as if these organs actually 

 function as such before complete fission takes place. 



The nerve ring is formed by the outgrowths from the nerve cord, 

 which have already been mentioned. New setae are formed very 

 quickly. I was not able to make out the method of their formation. 

 The nephridia are not formed until some time later. The portion 

 between the first two bundles of setae after the line of fission 

 lengthens out rapidly, and finally after the animal has Ijeen lying 

 .quiescent for some time, it gives a series of rajDid contractions, and 

 the two new individuals jerk themselves^ apart. 



Figs. xii. and xiii. show an individual in which the line of fission 

 is narrowing down. 



Fig. xiv. shows anotlier individual at tlie stage represented in 

 Fig. X. This individual also divided afterAvards. 



Fig. XV. shows a stage between those represented in Figs. viii. and 

 ix. Fig. xvi. shoAvs two new individuals immediately after fission. 



Chaetogaster victoriensis, sp. n. 

 External (Characters. 



Length. — The length varies from 6 to 9 mms. Average individuals 

 measure about 8 mms. 



The animal is much larger than C. atisfralis: it is less inclined 

 to disintegrate, contains more segments, and. consequently, the 

 asetigerous portion seems comparatively shorter. 



There is no clitellum. 



G. vicforien.s/s, like C. ausfralis, reproduces asexually by fission, 

 l)ut differs in that in this species secondary fission takes place as a 

 rule, before the primary fission is complete. 



The prostomium is circular, the mouth ventral, the anus terminal. 

 The setae are arranged in bundles as in C. ausfralis. Thei-e are 

 some fine hairs round the two ends of the animal. 



An average animal consists of about 20 segments. I could find 

 no individual in this species that had no trace of fission; in fact, 

 •each specimen not only showed signs of primary fission, but of 

 secondary as well. 



Movement takes place by means of a series of contractions and 

 expansions Avith the aid of anterior and posterior suckers, someAvhat 

 like a leech. 



The setae are arranged in bundles, and there are typically a pair 

 of bundles in each segment. Tlierc is also the asetigerous portion 

 foUoAved by the bundle in the- sixth segment. Eacli bundle consists 

 of from 5 to 9 setae. 



