POLYSTOMELLINAE 437 



406. Nonion grateloupi (d'Orbigny) (Plate XVI, figs. 9, 10). 



Nonionmagrateloupi, d'Orbigny, 1826, TMC, p. 294, no. 19; 1839, FC, p. 46, pi. vi, figs. 6, 7. 

 Noiiionina grateloupi, Fornasini, 1904, SOF, p. 12, pi. iii, fig. 5. 



Seven stations: 235; WS 76, 83, 88, 89, 93, 99. 



This species, so common in the warmer waters of the West Indian region, is com- 

 paratively rare in the Falkland area, and at most of the stations the specimens are very 

 small and pauperate. Very good and typical specimens were obtained however at 

 WS 83, 88 and 93, particularly at the latter station. The Type is missing. 



407. Nonion scapha (Fichtel and Moll). 



Nautilus scapha, Fichtel and Moll, 1798, TM, p. 105, pi. xix, figs. d-f. 



Nonionina scapha, Brady, 1865, RFND, p. 106, pi. xii, fig. 10; 1884, FC, p. 780, pi. cix, figs. 



14. 15- 



Sixteen stations : 228, 230, 235; WS 76, 83, 99, 210, 215, 217, 221, 225, 245, 248, 408, 409, 433. 



Widely distributed and often fairly common. Excellent specimens at WS 83, 99, 215, 

 217, 221 and 245 ; WS 217, in particular, furnishing a striking series. There is, as usual, 

 great variation both in the length and thickness of the test at the oral face, even in 

 specimens from the same station. At some stations, particularly 228 and WS 76, 408, 

 specimens approaching A^. labradorica (J. W. Dawson) (D. i860, TFL, p. 191, fig. 4; 

 D. 1870, GStL, p. 174, fig. 5) (G. M. Dawson, N. scapha var. labradorica) occur. 



408. Nonion pauperatum (Balkwill and Wright). 



Nonionina pauperata, Balkwill and Wright, 1885, DIS, p. 353, pi. xiii, figs. 25, 26. 

 Nonionina pauperata, Heron-Allen and Earland, 1908, etc., SB, 191 1, p. 342, pi. xi, figs. 16, 17. 

 Nonion pauperatum, Cushman, 1918, etc., FAO, 1930, p. 13, pi. v, figs. 4, 5, 7. 



Seven stations: 51, 388; WS 88, 89, 90, 92, 245. 



Never very common, but quite typical. An excellent series at WS 88. The specimens 

 are absolutely indistinguishable from those found in its locality of origin, the British 

 Isles. It is clearly a very widely distributed species, although the records are so few. 



Genus Nonionella, Cushman, 1926 



Whilst this paper was in course of preparation we had occasion to publish the 

 following paragraph (H.-A. & E. 1930, FPD, p. 193): "The genus Nonionella was 

 instituted by Cushman in 1926 (C. 1925, etc., LFR, 11, 1926, p. 64) supplementing 

 Nonionina. It includes those species having inaequilateral tests due to the chambers 

 developing lobed extensions on the ventral side at their umbilical ends, which cover the 

 umbilicus itself. It is questionable whether the genus has biological significance, 

 because the formation of inaequilateral tests is a common feature of variation in many 

 species of Nonionina, but for systematic purposes Nonionella is useful for the separation 

 of species which are normally asymmetrical". The much extended experience derived 

 from the examination of the Discovery material has amply confirmed our views. 



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