3 o DISCOVERY REPORTS 



137-139111. St. WS 801: Patagonian Shelf, 165 m. St. WS 807: Patagonian Shelf, 124-126111. St.WS 

 808: Patagonian Shelf, 1 10-106 m. St. WS809: Patagonian Shelf, 1 04-101 m. St. WS811: 

 Patagonian Shelf, 99 m. St. WS 813 : Patagonian Shelf, 106-102 m. St. WS 837: Patagonian Shelf, 

 102 m. St. WS 841 : Patagonian Shelf, 110-121 m. St. WS847: Patagonian Shelf, 57-84 m. St. 

 WS 871 : Patagonian Shelf, 336-342 m. ?St. MS 71 : S. Georgia, 110-60 m. 



Colony. As van Name (1945) has said, this species is so variable that 'an attempt to describe the 

 colonies in respect to form and size is impossible to fulfill '. Some colonies in the ' Discovery ' collec- 

 tions are relatively short and rounded, but many have a very characteristic long form tapering gradu- 

 ally to a fine point at the free end (PI. I, fig. 2). These long colonies were apparently attached by the 

 lower rounded end to a bottom of sand. The colour of the preserved colonies is usually some shade of 

 orange, yellow or brown, and the zooids sometimes show through the test, but not always. Generally 

 there are no obvious systems of zooids, but in a few cases the zooids could be seen to be arranged in 

 double rows, probably representing narrow oval systems. The surface is usually smooth and without 

 encrusting sand, but the interior of the colony may have a good deal of embedded sand. Some of the 



Table 3 



long narrow colonies appear to have lain horizontally on the sand during life, as sand is adhering to 

 the test at several places along the length of the colony (St. WS 808). In most of the specimens, the 

 surface-layer of the test has a characteristic appearance owing to the presence of many small round 

 pale yellow or orange-coloured vesicles. When the colony is cut open the zooids are seen to be closely 

 spaced. The longest colony in this collection is one of 63 cm. from the Patagonian Shelf (St. WS 808), 

 but one specimen from the same region is recorded as forming a 'portion of a colony weighing 

 300 g.'. 



Zoom (Text-fig. 2 A). The length of the zooids in the 'Discovery' material varies a good deal, 

 from about 6 to 18 mm., and depends largely on the development of the post-abdomen. The most 

 characteristic features of the zooid are: (1) the moderately developed and forwardly directed atrial 

 languet; (2) the small atrial opening placed a short distance back along the dorsal side of the thorax; 

 (3) the large branchial sac with ten to twenty-two rows of stigmata; and (4) the stomach with five or 

 six sharply defined undivided longitudinal folds. The number of rows of stigmata and the number of 

 folds on the stomach do not show any clear correlation with the size of the colony, as shown in Table 3. 



Gut. Van Name (1945) states that the stomach has usually four to six folds, but sometimes at least 

 eight or ten. Having examined several zooids from each of many colonies in the ' Discovery ' col- 

 lection, I have found the number of folds on the stomach to be always five or six, which I conclude to 

 be the normal number at least in specimens from the Patagonian Shelf. The rest of the gut shows no 





