12> 



V. GYMNOCOPA. 



Gymnocopaj Grube, Fam, Annel. 27- 



Char. Body exannular, asetigerous, gelatinous, glauciform, with a 

 series of compressed fins on each side : head distinct, tentaculated, 

 with " a kind of bristles " in the setaceous tentacula. Sexes separate. 

 Vascular system obsolete or very slightly developed. Swimmers. 

 Marine. 



Fam. I. TOMOPTERID^. 



ToMOPTERiDEA, Grube, Fam. Annel. 95. 



Char. Body elongated, elliptical, with compressed fins, little deve- 

 loped or obsolete towards the posterior extremity : segments not 

 numerous, and not divided by sutures. Head continuous with the 

 post-occipital segment, furnished with frontal tentacula, and with 

 very long lateral tentacular filaments, both containing a setiform 

 portion : eyes 2 : mouth ventral, edentulous. Fins or feet two-lobed, 

 without bristles. 



L TOMOPTERIS, Eschscholtz, 1825. 



Tomopteris, Grube, Fam. Nat. 96. 



Jolinstonella, Gosse's Ramb. Devon. Coast, 35G ; see also Gray, Ann. 

 &• Mag. Nat. Hist. ser. 2. xii. 150 & 199. 



Char. The only genus. 



1 . T. onisciformis. 



Tomopteris onisciformis, Grube, Fam. Annel. 96. 



Johnstonella Catharina, Gosse, Ramb. Devon. Coast, 356. pi. 25. 



Hab. The sea-coast of S. Devon, P. H. Gosse. 



Desc. " Body | inch long, \ inch in greatest diameter, flat, thin, 

 as transparent and colourless as glass. Head dilated on each side 

 into two lobes, which are flat, pointed, and leaf-like, extending late- 

 rally to a considerable distance. Along the posterior pair are soldered 

 a pair of excessively long, slender antennee, tapering to a fine point ; 

 they appear simple unjointed filaments, directed divergently back- 

 wards to a greater length than the body, and incapable of changing 

 in direction. The basal moiety of their length is invested with a 



