RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY l6l 



there at the time of his former visit he was unable to say, as the 

 anirnal is as transparent as the water in which it Hves, and may 

 easily escape observation. His attention was accidently directed to 

 its discovery. Along the edge of the pond there were numerous 

 linear white bodies, flaccid and motionless, which he at first took 

 for fragments of a bleached alga. From the uniformity of their 

 size he stooped to examine them more closely, when he noticed 

 others in the water, more transparent, lying on the sand and occa- 

 sionally moving suddenly and so actively as to send a little spray 

 above the surface. On transferring some of these bodies to a vial 

 he detected their nature. Subsequently the water was seen to swarm 

 with the little creatures. They were exceedingly sensitive, and 

 quickly die after removal. In life they were perfectly transparent 

 and colorless, and move actively at intervals with a sort of spasmodic 

 jerk, bending the tail downward and darting forward. After death 

 they become flaccid, dull, and white, and hence the appearance of 

 the multitude of dead ones on the shore. 



The Sagitta is interesting as being one of those peculiar animals 

 which have puzzled naturalists as to its exact relative position. It 

 is now usually regarded as the representative of an order of worms 

 with the name of Cluetoguatha. 



A species, Sagitta elegans, has been described by Prof. Verrill as 

 occurring at Wood's Holl, Vineyard Sound, and Gay Head, on the 

 New England coast, and he refers to a second undetermined species 

 occurring in Vineyanl Sound. 



The Sagitta of Atlantic City appears to differ from the former, 

 and also from all other described species found elsewhere, and ma}' 

 be readily distinguished from them by its greater number of man- 

 dibular hooks. It may be characterized as follows : 



Sagitta Falcidens. — Animal transparent, colorless ; body com- 

 pressed, elongated fusiform, with two pairs of lateral hemi-elliptical 

 fins, separated by intervals from each other and the broad obcordate 

 caudal fin, which is truncated posteriorly. Head obcordate, about 

 as broad as it is long. Pre-ordal series of spines, 6 or 7 in each, 

 minute ; postoral series. 18 in each, successively decreasing. Man- 

 dibular hooks, from 11 to 14 in each series, usually 12, besides an 

 immature one, scythe-shaped, yellowish brown in color. Length 

 about 3-4ths of an inch, width \Vz to 2 mm. Head i mm.; caudal 

 fin 1.5 to 1.75 mm. wide. Mandibular hooks 0.75 mm. long. 



At the same time as previously numerous mounds of the Balano- 

 glossus aiirantiaciis were observed. There were also noticed in the 

 same pond many projecting tubes of sand, which were found to 



