REPORT ON THE TUNICATA. 29 



Ascidiozooid the pigment masses scattered over the surface of tlie organs arc very con- 

 spicuous. 



In all these specimens from the Antarctic, the processes on the outside of the colony 

 are few in number and are very irregularly distributed. In the most crowded spot 

 there are only about three processes in a square centimetre, and on an average there is 

 probably not so much as one process in a square centimetre, while in several of the 

 colonies there are tracts of from 5 to 10 cm. in extent on which no processes are present. 

 The processes are mostly about 4 or 5 mm. in length. They are conical in their basal 

 part, with the branchial aperture at the apex of the cone, and having the terminal [lart 

 I )f the process extending outwards on the dorsal edge of the branchial aperture. This 

 terminal part of the process is flattened and expanded so as in some cases to approacli 

 the lanceolate form described by Savigny and Lesueur. It is also grooved along the 

 side next to the branchial aperture (PI. I. fig. 8). 



A small colony obtained at Station 204, off the Philippine Islands, is also proljably 

 referable to this species, but it is young, and the colony has not the usual shape (see 

 p. 34). 



Two small colonies, collected on September 10, 1873, off the coast of Brazil (see 

 p. 34), and the large decayed specimen from Station IGO (see p. 34), may also possibly 

 belong to this species. 



Pyrosoma sjjinosum, n. sp. (PI. II. tigs. 0-15). 



External Ap2iearance. — Shape, unknown. Size, over 4 feet in length. f*olour, 

 yellowish gre)^ semi-transparent. 



Ascidiozooids large, conspicuous. No large projections from the outer surface of the 

 colony. 



Test gelatinous, transparent. Covered on tlie outer surface with .small sharp- 

 pointed spines. Inner surface smooth and glistening. 



Mantle with a well-developed muscular system over the thoracic region of the Iwdy. 



Branchial Sac large, vessels very numerous, 



Dorscd Languets more than eight. 



Localities.— {I.) June 25, 1873; Station G9 ; lat. 38° 23' 0" N., long. 37" 21' 

 0" W. ; depth, 2200 fathoms; surf. temp. 71°, bottom temp. 36°-2. 



(2.) October 11, 1873 ; Station 133 ; lat. 35° 41' 0" S., long. 20° 55' 0" W. ; deptli, 

 1900 fathoms; surf. temp. 58°, bottom temp. 35°-4. 



This is the largest kind of Pyrosoma known, and although I have only had some 

 fragments of colonies to examine, I have no hesitation in forming a new species for it. 

 At Station 133 in the South Atlantic, 400 miles west of Inaccessible Island, a 



