SPECIES OF THE GENUS AULODRILUS. 



947 



and terminal. The worms do not reproduce asexually by 

 budding. 



Setce. — The setse of both the dorsal and ventral bundles begin 

 in the second segment, and are absent in a number of developing 

 segments in front of the hinder end of the body. 



There are three kinds of setae in the dorsal bundles : capilliform, 

 slightly hooked and doubly forked needles of the sigmoid type, and 

 oar-shaped setse with somewhat flattened or fan-shaped distal 

 extremity, which sometimes may end in a fine point. The 

 number of setse in a dorsal bundle varies from 8-10 of which 

 2-4 may be capilliform ; these are generally absent in the first 

 two or three setigerous segments, and hence begin in the 4th or 

 5th segment. 



A hair seta (text-fig. 1, A) is 99-1 04 /x in length, always 



Text-fiffure 1. 



Hair set.a ; B. Uncinate seta of a dorsal bundle; C and D. Dorsal setae flattened 

 near the distal end (oar shaped) ; E. Uncinate seta of posterior ventral bundle ; 

 F. Penial seta. X 540. 



longer but more slender than the needle. It is nearly straight 

 with a slight sickle-shaped curve and tapers to a fine point. 

 The needles of the orditiary kind (text-fig. 1, B) are, as usual, 

 doubly curved and slightly hooked at the distal extremity, 

 which is forked. In length this seta varies from 75-92 fj. ; it 

 bears a swelling or nodulus, which is situated much nearer 

 the distal extremity, the proportions of the distances from it 

 to the proximal and distal ends being about 2:1. The 

 prong on the outer side of the curve of the shaft is smaller 

 and much narrower than the one on the inner side, appear- 

 ing as fine as a line or a denticle ; in some preparations it 

 may be broken ofi", and then the seta appears as a single pointed 

 needle. The dorsal setae of the third kind (text-fig. 1, and D) 

 are flattened at the distal extremity and appear oar-like. They 



