22 W. A. HERDMAN. 



S. HEXAGONA, Quoy and Gaim. 



One damaged specimen from "Winter Quarters, 1. vi. 03, No. 8 hole" probably 

 belongs to this species. 



DOLIOLUM *p. 



Four imperfect specimens of the " nurse " form of Doliolum, measuring from 4 to 

 7 mm., were brought back from " 1. vii. 04. Lat. 55 44' S. ; Long. 95 43^' W. 

 5 fathoms." It 'is impossible to determine the species now. 



LAEVACEA. 



APPENDICULAPJID.E. 



OlKOPLEURA GAUSSICA. 



(Plate VII., figs. 14-17.) 

 Oikopleura gaussica, Lohmann, Zool. JB., Suppl. viii. (1905), p. 359. 



A small tube from the Winter Quarters in McMurdo Bay, labelled " 18. v. 03, 

 No. 4 Hole, Plankton," contains three specimens of a large Appendicularian. They 

 are not in very good condition, and all probably belong to the same species, and in 

 external form and in detailed proportion of the internal organs seem to agree better 

 with 0. gaussica than with 0. valdivise the two large Antarctic species described by 

 Dr. Lohmann.* The measurements of body and tail in these three ' Discovery ' 

 specimens are as follows : 



Trunk . . . 1*25 mm., 1'5 mm., 1*5 mm. 

 Tail ... 7 mm. 9 mm. 9 mm. 



This species was also found at " 3. i. 02, Lat. 66 52' S. ; Long. 178 15' E. " 

 one specimen: "7. i. 02, South of Pack"- 53 specimens; "11 Jan. 1902, Ross 

 Sea " one specimen ; and " 3-7 " six specimens. In some of these specimens the 

 trunk measures up to 3 mm. in length, and the tail is about five times as long as the 

 trunk, and may be as much as 2 mm. in width at its widest part. 



Our fig. 14 on Plate VII. shows the appearance, to the eye, of these ' Discovery' 

 specimens of (probably) 0. gaussica, and fig. 15 shows the tip of the tail enlarged. 

 Several sections through the tail are given in fig. 1G (A to D) to show the very 

 different degree of development of the muscle bands in different parts of the same 

 tail. D shows a case where the dorsal muscle band is co-terminous with the notochord, 



* Die Appendieularien des arktischen und antarktischen Gebiets, &c. Zoolog. Jahrb., Suppl. viii. (1905), p. 853. 



