80 DISCOVERY REPORTS 



At 30 cm. the gonad has disappeared but many of the zooids have two embryos in the brood pouch, 

 and this is the usual condition throughout the rest of the colony, with some variations in the state of 

 the ovary. 



This grading of sexual development in the zooids indicates that towards the base of the colony the 

 zooids are younger than those higher up the colony, and is to be expected in forms with a linear 

 arrangement of the zooids (e.g. Sycozoa) but not necessarily in D. cylindrica which has small oval 

 systems. In some at least of the colonies which have embryos the zooids contain very little or no food 

 in the gut, and it is likely that the zooids become moribund once the eggs are passed into the brood 

 pouches. Specimens collected in April and containing embryos had non-functional zooids and some 

 colonies lacked zooids altogether. None of the colonies in the collection showed any sign of the 

 accumulation of reserve materials or other provision for overwintering and how the species passes 

 through the winter is not known. 



Table 24 



Month May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. 



Well-developed male — — 2331 — 00 



Well-developed female — — — 0043 — 10 



With embryos — — — — — o o 1 o — 3 1 



(b) Feeding. The contents of the gut show one or two interesting features. In the branchial sac of 

 zooids in several colonies there was much coarse sand as well as organic matter (PI. VI, figs. 4, 5), but 

 the stomach and intestine showed no large sand grains, (PI. VI, fig. 3). Unless this is an artifact 

 produced in some way during collection or handling of the specimens, there seems to be some kind 

 of sorting mechanism at work between the branchial sac and the stomach, a feature noticed in other 

 and unrelated species (see p. 146). Coarse matter is present in the branchial sac right up to the 

 mouth of the oesophagus, but none enters the oesophagus. That the mechanism is not simply one 

 which excludes large particles is indicated by the presence of some diatoms in the intestine, equal in 

 size to the sand grains which are excluded. The oesophagus perhaps accepts mainly organic matter, 

 or particles with a smooth surface, but I do not know which of these characters is the important one 

 or how the selection mechanism works. There must be an accumulation of sand particles in the 

 branchial sac which is presumably cleaned at intervals by thoracic contractions expelling the whole 

 contents of the branchial sac. 



Distribution. Antarctic (Graham Land, Kaiser Wilhelm II Land, MacRobertson Land, South 

 Georgia, South Sandwich Islands), Subantarctic (Patagonian Shelf, Strait of Magellan). 



Genus Hypsistozoa Brewin, 1953 



Hypsistozoa fasmeriana (Michaelsen) (Text-fig. 22, PI. Ill, fig. 2) 



Distaplia j'asmeriana Michaelsen, 1924. 

 Hypsistozoa fasmeriana Brewin, 1953, p. 56. 



Occurrence. St. 935 : North Island, New Zealand, 84 m. 



Colony (PI. Ill, fig. 2). The single specimen of this interesting species is a colony with head 1-3 cm. 

 long and i-i cm. wide, borne on a stalk i-6 cm. long and 0-7 cm. wide. The head is greyish brown and 

 the stalk dull pale orange ; both are smooth and without any encrusting matter. Rows of zooids are 

 visible through the test; the systems are in fact long narrow elipses, but so narrow that the zooids 

 have the appearance of being arranged in double rows. The common cloacal openings, of which there 

 are several, are scattered on the surface of the colony, but are largely confined to the distal part. Each 

 opening is round or oval and is bordered by a projecting rim of test. 





