54 DISCOVERY REPORTS 



formed from either edge. The development of the first few tubes in many specimens 

 exhibits great regularity, the tubes being spaced evenly round the rim. This regularity 

 seldom persists beyond the formation of the third tube, specimens with five to seven 

 tubes often having them very irregularly disposed. 



After death there is a tendency for the chitinous sides of the tambourine to collapse 

 and come together, with the result that the flat sandy belt folds inwards and forms an 



encircling tube. 



The earHest stage of Vanhoeffenella observed is oval with a tube at each extremity. 

 The smallest specimen seen measured only 0-45 mm. in greatest diameter, including the 

 tubes. It was sessile on a pebble at WS 51, attached by protoplasm extending from the 

 two tubes. Development proceeds at first by an expansion of one side of the oval from 

 which a third tube is extended, and later by constant enlargement of the rim with the 

 formation of additional tubes. The greatest diameter of the adult ranges between i -o and 

 2-0 mm. (including tubes). Average diameter about i-o mm. 



Specimens apparently multiplying by fission have been found. In one case this 

 proceeds by contraction of the specimen, the rims being pinched in towards each other. 

 In another much larger specimen, a sandy rim has commenced to grow across the 

 chitinous membrane. 



Vanhoejfenella is not a mud-feeder. The protoplasmic body is large and opaque but 

 not loaded with mud and Diatoms like many of its relatives. 



The distribution of the type round South Georgia is confined to shallow water, 

 100-270 m. There is one remarkable exception which appears to be distinct. 



39. Vanhoeffenella oculus, sp.n. (Plate I, fig. 22). 



One station : WS 334. 



A single specimen found at this station at the abnormal depth of 3705 m. presents 

 differences which appear to be worthy of specific distinction. In form the test is 

 an almost perfect oval and the tubular extensions, two in number, are small, purely 

 chitinous and of the frailest kind. They might easily be entirely overlooked. The 

 specimen is presumably a dead individual, as there is no trace of protoplasm within the 

 central diaphragms, and the sandy rim which is constructed of the finest material has 

 collapsed to form a tube. Similar specimens occur in deep water in the Antarctic area. 

 Greatest width o-6 mm., least width 0-5 mm., exclusive of the rudimentary tubes. 



Genus Pelosina, Brady, 1879 



40. Pelosina rotundata, Brady. 



Pelosina rotundata, Brady, 1879, etc., RRC, 1879, p. 31, pi. iii, figs. 4. 51 1884, FC, p. 236, 



pi. XXV, figs. 18-20. 



Pelosina rotundata, Cushman, 1918, etc., FAO, 1918, p. 55, pi. xxi, figs. 4-6. 



Ten stations: 27, 30, 140, i43> i44> 148; WS 25, 154; Drygalski Fjord; MS 68. 



Frequent to common at nearly all stations and quite typical, the test being constructed 



