404 Transactions of the Society. 



foot is not well marked off, and body, foot, and toe follow each other 

 without much distinctness. The foot-gland is elongated and club- 

 shaped and apparently single. 



The mouth is situated in the usual position on the ventral halt 

 of the front of the head ; around the mouth are four groups of five 

 or six fairly long stiff sense-hairs, and outside these there are the 

 usual four patches of vibratile cilia. The mouth is oval in shape, 

 and guarded by a wreath of short, closely-set, overhanging, stiff 

 hairs. The mastax, oesophagus, stomach, ovary, lateral canals, and 

 rest of the anatomy are quite normal of Synchseta type. One 

 uncus of the jaws is represented in fig. 14a. The* egg, when ex- 

 truded, is carried about for a time, attached by a thread, but often 

 becomes detached. I have observed an individual carrying two 

 eggs. It is oval in shape, 75 /u, (g^ in.) long by 58 //, (^- in.) 

 broad. 



In swimming this Synchreta sails in long graceful curves, 

 without undue haste, and reminds one of the flight of the swallow 

 through the air. When once seen this species can be recognised 

 by this mode of swimming, which is very different from that of 

 the other species. 



The male has not yet been observed. 



I have been very successful in preserving and mounting this 

 animal fully extended, and showing all its characteristic pecu- 

 liarities. 



The size varies a good deal according as the animal is 1 young or 

 full grown, from 181 p to 265 fi (y^ in. to ^ s in.). The width 

 across the auricles is very nearly the same. 



Its habitat, as far as known, is the open sea round Helgoland, 

 near Dundee, and the Bay of Naples, appearing in the summer 

 months from May. 



Synchaeta monopus Plate. 

 PI. VI. fig. 12. 



BIBLIOGRAPHY. 



Plate, L. H. — Ueber die Rotatorienfauna des bottnischen Meerbusens, etc. 



Zeitschr. f. wiss. Zool., Band 49, 1890, pp. 1-42. 

 Levander, K. M. — Wasserfauna in der Unigelrang von Helsingfors. Acta 



Soc. pro Fauna et Flora Fennica, Helsingfors, 1894, pp. 1-72, 2 pis. 



Spec. Char. — Body a greatly swollen bag, very thin-walled and 

 extremely transparent, terminating in a very small foot with single 

 toe. Head small, with four frontal styles and small auricles. 

 Eye red, cervical. Size 254 //, ( To -q in.) long by 164 /jl ( t £ 3 in.) 

 broad. Marine, pelagic in the Baltic. 



This remarkable pelagic marine species was named by Dr. 



