TUNICATA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 97 



for an Ascidia. The branchial sac is also thick, and both mantle and branchial sac are 

 of a distinctly pinkish colour which may be the remains of the orange-red that SLUITER 

 records. There are twelve moderate-sized tentacles, and the horse-shoe shaped dorsal 

 tubercle is very large, reaching up to the base of the tentacles. It seems larger than in 

 SLUITER'S specimens, in which, however, the dorsal tubercle is recorded as being rather 

 variable. 



SLUITER states that no teeth are present on the dorsal lamina ; but I find that in 

 the Scotia specimen the dorsal lamina has marked denticulations along its free edge, 

 amounting in one part to short tentacular languets. But still I have no doubt that 

 my specimen belongs to SLDITER'S species, and that the dorsal lamina must be regarded 

 as somewhat variable in character. The viscera on the left side of the body are 

 unusually large and opaque. 



Family DISTOMID^E. 



Colella pedunculata (Quoy and Gaimard). 



T Sycozoa sigillinoides, Lesson. 

 1 Colella tenuiccudii, Herdman. 

 ? Colella umbellata, Michaelsen. 



One colony having a stalk bifurcated near the top and bearing two " heads " was 

 found at Station 346 on Burdwood Bank, 56 fathoms, on December 1, 1903, and presents 

 to some extent characters recalling all the species named above. In the branching of 

 the peduncle it is like MICHAELSEN'S C. umbellata from the Falklands ; in the general 

 appearance of the " head," however, it is more like QDOY and GAIMARD'S C. pedunculata, 

 found by the Challenger at the Straits of Magellan, the Falkland Islands. Kerguelen, 

 etc. The long slender stalk recalls the Australian C. tennicaulis ; and it is possible 

 that LESSON'S Sycozoa sigillinoides may be identical with one or more of these other 

 named forms. Both the "heads" are, unfortunately, in the single colony in a very 

 ragged condition possibly dead when collected so that the more minute characters 

 of the Ascidiozooids cannot be determined. 



Holozoa cylindrica, Lesson. (Plate, fig 2.) 



(?) igntitus, Herdman, Challenger Report, ii., 1886, p. 251. 



Julinia amtralis, Caiman, Quart. J. Micr. Sci., 1894, p. 1. 



Distaplia ignota, Herdman, Report on "Southern Cross" Tunicata, Brit. Mus., 1902, p. 197. 



Holozoa cylindrica, Less. Hartmeyer, in Bronn's Tier-Reichs, "Tunicata," 1909. 



This large and apparently abundant Antarctic species was obtained by the Scotia 

 Expedition at the following localities : 



I. Station 346, Burdwood Bank, 56 fathoms, December 1, 1903. Seventeen 

 fraoments from 10 to 30 cm. in length by 2 to 4 cm. in diameter. All 



O _ 



in bad condition, soft and partly macerated, with many other animals, 

 Hydroids, Polyzoa, etc., entangled in the irregular, ragged surface. 

 (ROY. soc. EDIN. TRANS., VOL. XLVIIL, 315.) 



