7 8 DISCOVERY REPORTS 



Gut. The oesophagus is narrow and of moderate length. In some colonies the wall of the stomach 

 (st.) is distinctly marked with many fine ridges, but in others the wall is almost smooth externally. 

 Sluiter does not describe any markings on the stomach of his type specimens, and his figure shows 

 none. 



Gonads. The gonads in Sluiter's specimens were evidently not very well developed, only a group 

 of small testis follicles being present, and no trace of an ovary. Sluiter concluded that the colonies 

 were unisexual. 'Discovery' specimens collected in February and March show a variety of sexual 

 stages. In one colony some zooids are seen with a group of about twelve testis follicles (t) and a few 

 small ova (ov.), and other zooids have a testis and quite large ova. The colony from the South Orkney 



1.0 



Text-fig. 21. Distaplia colligans Sluiter (St. MS 63): Zooid. 



Islands has zooids with only the ovary present and no testis. It is likely that Sluiter's two specimens 

 were in the early male phase. The gonads are situated beside the loop of the intestine and scarcely 

 project from the body except when at the height of their development. Only in some colonies from 

 South Georgia and the South Orkney Islands is there any sign of a brood pouch ; the zooids have a 

 small sac-like projection from the dorsal body wall behind the atrial opening, evidently in the early 

 stages of development. 



Remarks. All these colonies, with the possible exception of the ones from St. 476 and St. 11 13, 

 are in good agreement with Sluiter's type specimens of D. colligans, although the new specimens 

 differ slightly in having markings on the wall of the stomach, and in the larger size of the zooids. 



The single colonies from St. 476 and St. 1 1 13 (PI. Ill, fig. 3) are larger (2 cm. in diameter and 7 cm. 

 long respectively) and paler than those already described. The zooids also are much larger, reaching 

 8 mm. in length when fully expanded. In other respects, however, they are similar and I am inclined 

 to think that the differences may be due to the stage of the annual cycle at which the colonies have 

 arrived. 





