SALPID^. 53 



we have taken from Lieutenant Thomas's preserved speci- 

 mens, guided and corrected by the drawing from the living 

 animal by Sars, whose description we think it best to 

 follow. 



Salpa runcinata, Chamisso. 



Chamisso, de Salpa, p. 16, f. 5. — Quoy and Gaimard, Voy. Astrol. Zool. 3, pi. 87, 

 f. 1-5. — Sars, Fauna littoralis Norwegise, pi. 8, f. 44, 45, and pi. 9, f. 1-24. 



Solitary State. (PI. E, fig. 5.) — Body oblong, anterior extre- 

 mity rounded, posterior truncated, beneath gelatinous and flat, 

 above depressed in front, elevated and cartilaginous behind, where 

 it is furnished with seven keels, gradually disappearing anteally, 

 produced into short spines posteally. Both apertures of the 

 branchial sac terminal. Muscles of respiration nine, placed in 

 the ventral side, three anterior and three posterior, approximated 

 in the middle. 



Aggregate State. (PL E, fig. 6: the individuals represented 

 are not so elongated as when full grown.) — Body gelatinous, 

 ovate, slightly depressed; beneath plane, above convex, produced 

 at each extremity into a conical acuminated appendage. Ori- 

 fices of the branchial sac beneath, at the bases of the appendages. 

 Muscles of respiration (besides those of the apertures) six, placed 

 in the ventral side, four anterior and two posterior, approximated 

 in the middle. 



Sars has found another species, which he refers to the 

 Salpa spinosa of Otto, in the Norwegian seas. It will very 

 probably be found also among the Hebrides. The posterior 

 extremity of the solitary individual is furnished with two 

 long straight spines; the aggregate individuals have an ovate 

 body, rounded anteriorly, produced into a short pyramidal 

 cartilaginous spine posteriorly. These characters will en- 

 able our naturalists to recognise it. 



The preceding enumeration of the British species of 

 TuNicATA, though far exceeding in detail any account of 

 them hitherto published, is oifered as a mei-e outline of a 



