74 THE VOYAGE OF H.M.S. CHALLENGER. 



Atlantic, on April 26, 1876), both anteriorly and posteriorly to the nine chief bands. 

 These are indicated in Traustedt's figures. 



Where it is present, the chain of embryos is longer and narrower than is repre- 

 sented in Traustedt's figures' of this species. This last remark applies to all the solitary 

 forms in the collection. They have the embryonic chain exactly in the position shown 

 by Traustedt, but it is always long and narrow. 



The aggregated forms vary considerably both in shape and size. Most of the 

 specimens in the collection are 5 mm. or 6 mm. in length, but some extend up to 1 cm. 

 The processes of the test at the anterior and posterior ends of the body are longer and 

 sharper in the specimen obtained on April 27, 1876, than is represented in Traustedt's 

 figures. 



The arrangement of the nervous system, dorsal tubercle, and neighbouring parts, in 

 a specimen of the aggregated form collected on April 26, 1876, is shown in PI. VII. 

 fig. 10. The ganglion is of rounded form, and has a large pigmented sense-organ 

 (ocular) placed on its anterior end. The dorsal tubercle is elongated antero-posteriorly, 

 and is slightly curved. The peritubercular area is continued posteriorly into a weU- 

 marked epipharyngeal groove (PI. VII. fig. 9,./.). The point where the dorsal lamina 

 becomes free from the mantle is shown at k. The dorsal lamina is marked by trans- 

 verse bands of ciliated epithelium (PI. VII. fig. 10, d.L). 



Salpa runcinata-fusiformis, Chamisso — Cuvier (PL VI. figs. 5-12). 



SaljM fusiformis, Cuvier, Ann. du Mus., torn. iv. p. 382, ISOi. 



SaljM runcinata, Chamisso, De Animalibus, &c., p. 16, 1819. 



Salpa runcinata-fusiformis, Krolin, Ann. d. Sci. Nat. (ZooL), ser. 3, torn. vi. p. 112, 1846. 



Salpa runcinatafusiformis, Traustedt, loc. cit., p. 370, which see for further synonymy. 



This well-known species is the second commonest in the Challenger collection ; both 

 solitary and aggregated forms, and especially the latter, having been taken at a laro-e 

 number of localities. As a rule, the aggregated forms occurred in far greater numbers 

 than the solitary. 



The following is a list of the localities, and the number of specimens from each : — 



(1.) December 27, 1873; Station 145a, ofi" Prince Edward Island, in the Southern 

 Ocean ; lat. 46° 41' 0" S., long. 38° 10' 0" E. ; surf. temp. 41°-5 ; many specimens of the 

 aggregated form (in bad condition). 



(2.) February 3, 1874 ; near Heard Island, in the Southern Ocean ; lat. 52° 20' 0" S., 

 long. 72° 14' O" E. ; surf. temp. 38° ; one specimen of the solitary form (?), in bad 

 condition, along with a Salpa, which is probably a bad specimen of the solitary form 

 of Salpa cylindrica. 



(3.) February 11, 1874; Station 152, Antarctic Ocean; lat. 60° 52' 0" S., long. 80° 20' 

 0" E.; surf temp. 3 4° '5; about one hundred and sixty specimens of the aggregated form 

 (many of them large), and one large and several small specimens of the solitary form. 



' Loc. cit., tab. ii. figs. 35 and 36. 



