1911] Michael: Chaetog)mtha of the San Diego Region. 43 



Seizing jaic.s (pi. 4, figs. 31, 32), 7 to 8 in number. Curvature about 

 33 per cent. Points of same general form as those described by Krum- 

 bach (1903) for S. furcata, the curvature along the back being greater 

 than along the edge so that apex of point lies toward edge of jaw. Point 

 inserted about 27 per cent of its height into shaft. Base of point and 

 top of shaft converge on approaching edge of jaw. Pulp evenly distrib- 

 uted throughout canal, the latter being displaced toward back of shaft. 

 Pulp-canal extends into the point from 66 to 75 per cent of the height 

 of the point. Apex of canal lies very near back of point. Older jaws 

 sometimes present a swollen place in the pulp slightly below point. The 

 convergence of top of shaft and base of point is more marked in the 

 older jaws. 



During the siimm«r of 1907 I had the opportunity of examin- 

 ing a large number of individuals of this species alive, and the 

 characters presented forcibly remind one of Conant's (1895) 

 description and figure of Sagitta hispida. Covering the body at 

 intervals, arranged symmetrically on the two sides forming 

 twelve longitudinal rows, are numerous tactile hairs which 

 present a remarkably hispid appearance. This appearance 

 ceases entirely when the animal is killed and preserved. The 

 corona ciliata was also found to agree very closely with that 

 figured by Conant (1895) for S. hispida. It is rather broad, 

 somewhat sinuous, and roughly resembles a ten-pin in outline. 

 It extends from in front of the eyes to a point about half way 

 from the head to the ventral ganglion, being more on body than 

 head. 



At first I was inclined to think that S. hispida was a synonym 

 for 8. hipunctata, but careful comparison has convinced me that 

 they are not the same species. The tail of S. hipunctata is pro- 

 portionally too short, the posterior fins present more than 50 

 per cent in front of tail-septum, and the general appearance of 

 the body is much different. 



S. hipunctata bears a strong resemblance to S. decipiens. 

 In fact the similarity is so great that I made (1908) the mistake 

 of identifying my material as S. decipiens. The nature of the 

 mature ovaries is much the same, and nearly all the propor- 

 tional measurements overlap to a surprising extent. There are, 

 however, a few points of difference. The tail in S. decipiens 

 varies from 28 to 40 per cent, the seizing jaws are 5 to 6, the 

 number of anterior and posterior teeth is somewhat greater, and 



