70 DISCOVERY REPORTS 



82. Hippocrepinella hirudinea, Heron-Allen and Earland (Plate VII, figs. 1-9). 



Hippocrepitiella hirudinea, Heron-Allen and Earland, 1929, etc., FSA, 1932, p. 258, pi. i, figs. 

 7-15- 

 Thirteen stations: 27, 28, 45, 123, 126, 140, 143, 144, 148, 149; WS 28, 42; MS 68. 



Test free, monothalamous, irregularly cylindrical, occasionally curved, rounded at 

 the extremities which are sometimes slightly clavate, sometimes tapered off". Wall thin, 

 smooth and neatly finished, shining or "matt", often covered with fine transverse 

 wrinkles. Apertures, central and terminal, usually varying in size, one being more 

 pronounced than the other. Colour varying from light to dark grey. Size up to 2-0 mm. 

 in length, 0-5 mm. in width. 



This species, which is the genotype, is very variable in size and general appearance, 

 while very constant in its specific features. Although many specimens are to be found in 

 perfect condition, the majority exhibit compression, distortion or shrinkage in varying 

 degrees. The explanation is to be found in the condition of the interior of the test. We, 

 ourselves, have laid open many tests, and Mr J. T. Holder, F.R.M.S., has been so good 

 as to cut serial longitudinal sections of others. The cavity is found to be more or less 

 compactly filled with an ingested mass of food-stuft's, principally Diatoms (Figs. 2-3), 

 and it depends upon the compactness of this mass, whether or not the test preserves its 

 outline after death. Mr Holder's sections have also been useful, in demonstrating the 

 fineness of the material used in construction, and the almost total absence of larger 

 particles of sand. 



Occasional specimens noticed at several stations, notably Sts. 140 and 144, exhibit a 

 number of irregularly placed pustular openings in the walls of the test, the origin of 

 which is obscure. From the nature of the openings, they are clearly not due to external 

 agencies, but originate inside the test. They may be subsidiary openings for the emission 

 of young individuals, but it seems more probable that they are made by minute or- 

 ganisms, perhaps Nemertine worms, which have been ingested with the mud-mass as 

 food, and have successfully eaten their way through the wall of their captor. 



Hippocrepinella hirudinea is very common at St. 45, common at Sts. 144 and 148, all 

 three of which are in or ofl^ Cumberland Bay. At the other stations it is rare or very rare. 

 In depth the range extends between 100 and 346 m. 



An abnormal specimen found at St. 45 is bifurcate at one extremity, each of the arms 

 bearing the usual aperture (Plate VII, fig. i). 



83. Hippocrepinella hirudinea var. crassa, Heron-Allen and Earland (Plate VII, figs. 



13-15)- 



Hippocrepinella hirudinea var. crassa, Heron-Allen and Earland, 1929, etc., FSA, 1932, p. 259, 

 pi. ii, figs. 1-3. 



Two stations: 660; WS 32. 



General characteristics as in the species, but the test is much broader in proportion 

 to its length, of an elongate oval or fusiform shape, round in section or compressed. 



