96 DISCOVERY REPORTS 



Tentacles. Only four tentacles (tn.) were seen, although Sluiter noted eight. 



Branchial sac. There are twelve rows of stigmata in most zooids examined, each row with about 

 eighteen stigmata. The three longitudinal branchial bars customary in the genus are present. The 

 dorsal lamina is a narrow membrane. 



Gut. The gut is confined to the posterior part of the zooid. It consists of a short curved oeso- 

 phagus (oe.), a conical stomach (st.) with nine folds but completely lacking a pyloric caecum, and an 

 S-shaped intestine and rectum. The anus (a), which lies opposite the 7th row of stigmata, has a plain 

 margin. 



Gonads. No gonads were present in any of the zooids examined. 



Remarks. Few species of either Botryllus or Botrylloides have been described from the North 

 Island of New Zealand or the Australian coasts, and the present specimen does not agree well with 

 any of them. The main points on which I base identification are the absence of a pyloric caecum and 

 the presence of nine folds on the stomach. But there must remain some doubt about this identification 

 because reliable characters are few in the botryllids, and the nearest record of B. separatus is from the 

 vicinity of Borneo. 



Distribution. Indonesia; North Island, New Zealand. 



Genus Polyzoa Lesson, 1830 



Polyzoa opuntia Lesson (Text-fig. 33 A; PI. V, fig. 1) 



Polyzoa opuntia Lesson, 1830, p. 437. 

 For synonymy see van Name 1945, p. 236. 



Occurrence. St. 145: S. Georgia, 26-35 m. St. I2 3° : Magellan Strait, 27 m. St. 1902: Pata- 

 gonian Shelf, 50-80 m. St. WS71: Falkland Islands, 82-80 m. St. WS75: Falkland Islands, 

 64-104 m. St. WS86: Patagonian Shelf, 151-147111. St. WS95: Patagonian Shelf, 109-108 m. 

 St. WS221: Patagonian Shelf, 76-91 m. St. WS788: Patagonian Shelf: 82-88 m. St. WS798: 

 Patagonian Shelf, 49-66 m. St. WS 834: Patagonian Shelf, 27-38 m. St. WS 837: Patagonian Shelf, 

 95-102 m. St. MS 33: S. Georgia, 40 m. St. MS 64: S. Georgia, 7-15 m. St. Port Stanley, Falkland 

 Islands, on shore. 



External appearance (PI. V, fig. 1). The colony of this species, although variable, is well known 

 and characteristic, and needs no further description. 



Larva (Text-fig. 33 A). The larva has an ovoid trunk measuring about o-8 mm. from the anterior 

 end of the papillae to the base of the tail. Behind the three papillae is a number of ampullae forming 

 a complete ring round the anterior end of the trunk. There is a single black sense organ. The tail is 

 about 1-5 mm. long, excluding the fin of test which projects about o-6 mm. beyond the end of the 

 tail. 



Biology. Larvae were found in colonies from the Patagonian Shelf and Falkland Islands in 

 December, February, March and June, and in colonies from the Magellan Strait in December. No 

 larvae were present in the colonies from S. Georgia. 



Remarks. Arnback (1950) separated P. opuntia Lesson and P. coccinea Cunningham, which 

 van Name (1945) regarded as synonymous species. The distinctions which Arnback proposed are: 

 (1) the difference between seven longitudinal bars (P. opuntia) and eight bars (P. coccinea) on the left 

 branchial wall ; and (2) differences in the form of the colony. The colony is very variable and I doubt 

 whether these distinctions are sufficiently great or constant in the genus to justify this course. 



Distribution. Subantarctic (coast of Argentine, Falkland Islands, Kerguelen, Tierra del Fuego), 

 Antarctic (South Georgia, Heard Island). 





