4i6 DISCOVERY REPORTS 



by Cushman (C. 1925, etc., LFR, vol. i (1925), p. 42, pi. vi, figs. 11-12) as D. ornaiis- 

 sima. From their distribution, it seems possible that both D. malovensis and D. plana are 

 species of Southern Pacific ancestry which have not as yet attained much extension on 

 the Atlantic side of Cape Horn. 



Brady's identification of his form with the Valvidina pileohis of d'Orbigny (d'O. 

 1839, FAM, p. 47, pi. i, figs. 15-17) has always seemed to us to be doubtful and can no 

 longer be entertained. The Type of Valvulina pileolus could not be found in Paris, but by 

 the courtesy of Prof. Marcellin Boule we were allowed to examine d'Orbigny 's material 

 from Arica, Peru, the original locality for the species. The sample was a coarse MoUuscan 

 and Echinoderm sand with very little fine material, in which, however, we succeeded in 

 finding four specimens which are unquestionably d'Orbigny 's organism. It is evident 

 that his figures are much conventionalized, particularly the side view (fig. 17). The large 

 boss shown in the basal view (fig. 16), to which may be attributed the incorrect assigna- 

 tion of the species to his genus Valvulina (he refers in his text to the "valvule arrondie, 

 assez saillante "), was, almost certainly, a young attached specimen, or bud. The whole of 

 the group of Discorbis characterized by beaded dorsal sides is subject both to budding 

 and plastogamy, and two of our specimens from Arica show evidence of it in the shape 

 of eroded umbilici. 



D'Orbigny 's species is thus found to be very different from the organism figured by 

 Brady. It has but four or five chambers to the convolution as against eight or more in 

 Brady's and in this respect is much nearer to D. malovensis, but it cannot be confused 

 with either. The ventral aspect of d'Orbigny 's species, with its rows of beads converging 

 to a deeply sunk umbilicus, is very distinctive, and, except in the differing number of 

 chambers, very suggestive of the base of D. pulvinata, Brady, another Pacific species. 

 Altogether the D. pileohis of Brady is such a well marked form, and possesses such a 

 definitely localized range, that it deserves specific separation, and we propose for it the 

 new name Discorbis australensis. 



352. Discorbis chasteri (Heron- Allen and Earland). 



Discorbina mitnitissima. Chaster, 1S92, FS, p. 65, pi. i, fig. 15. 



Discorhina chasteri, Heron-Allen and Earland, 1913, CI, p. 128, pi. xiii, figs. 1-3. 



Six stations: 388; WS 79, 83, 88, 92, 409. 



This minute but very widely distributed species is not uncommon at WS 92, rare at 

 the other stations. The specimens are quite typical and all of the round type. No oval 

 or spinous forms were found. 



353. Discorbis coronata, sp.n. (Plate XIV, figs. 25-30). 

 Two stations: WS 88, 245. 



Test free, minute, hyaline, depressed, almost scale-like, inaequilateral, consisting of 

 i|-2 convolutions with nine chambers in the final convolution; sutural lines distinct 

 and curving, peripheral edge broadly carinat^ and recurved. 



The dorsal side is convex, but flattened in the centre. The chambers of the outer 



