64 DISCOVERY REPORTS 



appear to have been attached to sponge spicules, judging by the shape of the scar of 

 attachment. 



69. Tholosina vesicularis (Brady) (F 67). 



Eighteen stations: 17, 20, 27, 31, 126, 136, 144, 148, 149; 53' 00' S, 34'' 22' W; WS 33, 40, 42, 51, 

 110, 154, 363, 418. 



Very common indeed at St. 144 and common at Sts. 27, 126, 148, WS 33 and no, 

 frequent to rare at the remaining stations. The specimens, with few exceptions, are quite 

 typical. At St. 144, in addition to the type, specimens were seen sessile on sponge 

 spicules, the two apertural tubes being extended along the spicule in each direction. At 

 St. 27 a single specimen had long collapsed chitinous tubes extending freely from the 

 ends of the usual attached tubes. 



70. Tholosina vesicularis var. erecta, Heron-Allen and Earland (F 68). 



Recorded with hesitation, no perfect specimen having been seen. Fragmentary tubes, 

 which may belong to this variety, were noticed at Sts. 30, 129, WS 25 and 33. 



Genus Armorella,^ Heron-Allen and Earland, 1932 



Test free, monothalamous, approximately spherical, furnished with a variable number 

 of extended tubes of different length, with an aperture at the end of each tube. Wall 

 firm, but very thin, constructed of fine sand. Diatoms and sponge spicules incorporated 

 with much cement, occasional larger sand grains and spicules projecting from the other- 

 wise smooth and rather shining surface. Interior surface similarly smooth. Colour 

 light grey. 



This is a very distinctive form, closely allied to Thnrommiiio and Tholosina, its 

 affinities probably lying with the latter genus. Small specimens furnished with short 

 tubes, or remains of broken tubes, are very like TJinramnii?ia papillata in their spherical 

 form, but a series of specimens links them up with the large and multitubular individuals, 

 which have no resemblance to that species. Moreover the broken tube ends are very 

 unlike the aperture of Thiirarnmina. 



Small sponge spicules are often employed to a considerable extent as building material, 

 being smoothly incorporated in the wall. In specimens from St. 144, they play a larger 

 part than usual in construction, the sphere in some cases being built round a bundle of 

 spicules, the ends of which may project to an extent equal to the diameter of the test. 

 This spicular construction to some extent also modifies the shape of the test, which 

 tends to become polyhedral instead of spherical. Such tests are probably not evidence of 

 selective powers, or only in a limited degree comparable with the use of spicules in 

 Psammosphaera rustica. But these projecting spicules would undoubtedly serve a useful 

 purpose in supporting the organism in the surface layer of mud, and this would be of 

 value to the animal, which is not one of the mud-eaters. The protoplasmic body is large, 

 but not loaded with mud and Diatoms as in many Arenacea. 



1 In memory of Armorel Daphne Heron-Allen, who died July 3, 1930, aged 22. 



