440 DISCOVERY REPORTS 



it disclosed a sharp-edged form with twelve sUghtly inflated chambers ; the sutures and 

 fossettes are deeply stained with iron, the rest of the shell white. It is clearly not the 

 Type of P. articulata, but is possibly a fossil from the Vienna beds, suggesting P.flexiiosa 

 (d'O. 1846, FFV, p. 127, pi. vi, figs. 15, 16) aUhough the chambers are not so numerous 

 as in d'Orbigny's figure. 



415. Elphidium (Polystomella) alvarezianum (d'Orbigny) (Plate XVI, figs. 24, 25). 



Polystomella alvareziana, d'Orbigny, 1839, FAM, p. 31, pi. iii, figs. 11, 12. 

 Elphidium alvarezianum, Cushman, 1918, etc., FAO, 1930, p. 18, pi. vii, figs. 1-3. 



Eight stations : 48, 51; WS 83, 86, 92, 99, 215, 408. 



D'Orbigny recorded his species from the coast of Patagonia and the Falkland Islands. 

 It is a fairly distinctive form, and is probably widely distributed in shallower waters than 

 that from which most of the Discovery material emanated. But it is fairly abundant, 

 and excellent specimens occur at several stations, notably 48 and WS 86. D'Orbigny 

 records the colour as being "bluish white", presumably this merely refers to a hyaline 

 condition. The majority of specimens present this appearance. 



Breadth, about 0-65 mm.; width, 0-55 mm.; thickness at oral face, 0-25 mm. 



The Type specimen is not to be found in Paris. 



416. Elphidium (Polystomella) magellanicum, sp.n. (Plate XVI, figs. 26-28). 

 Two stations: WS 89, 90. 



Test free, hyaline, compressed, exhibiting five to six chambers in the outer convolu- 

 tion. Sutures strongly depressed, chambers slightly inflated, giving a markedly lobulate 

 peripheral edge. The sutural depressions are filled with very finely granular matter, 

 giving a somewhat snow-like surface, contrasting strongly with the inflated glassy 

 chambers, which are generally quite transparent. Underneath the granular snow-like 

 matter in the sutures, the "fossettes" are concealed, but in young specimens they are 

 plainly visible. 



Dimensions, breadth, up to 0-35 mm.; width, 030 mm.; thickness at oral face, 

 0-I2 mm. 



The species occurs only at WS 89 and 90, which are in shallow water (23 and 82 m.) 

 on the opposite (north and south) sides of the eastern entrance to the Straits of 

 Magellan. In some respects they resemble the specimens figured by us from the West of 

 Scotland (H.- A. &E. 1916, FWS, p. 281, pi. xliii, figs. 11-19) as P.faba, Fichtel and 

 Moll, but they are more compressed and more lobulate, and the "fossettes" are much 

 more distinct. 



417. Elphidium (Polystomella) lessonii (d'Orbigny) (Plate XVI, figs. 29, 30). 



Polystomella lessonii, d'Orbigny, 1826, TMC, p. 284, no. 6; 1839, FAM, p. 29, pi. iii, figs, i, 2. 



Polystomella macella, Brady, 1884, FC, pi. ex, fig. 9. 



Polystomella lessonii, Fornasini, 1904, SOF, p. 13, pi. iii, fig. 9. 



Elphidium lessonii, Cushman, 1918, etc., FAO, 1930, p. 22, pi. ix, figs. 1-4. 



Fourteen stations: 48, 51 ; WS 71, 73, 76, 83, 86, 88, 93, 97, 210, 225, 246, 248. 



