1891.] THE 'challenger' expedition. 441 



15. ScALARiA DisTiNCTA. (Plate XXXV. fig. 15.) 



Testa elongata, gracilis, alba ; anfractus perconvexi, lente aecres- 

 centes, costis tenuibus circiter 16 (Jiic illic una crassiore) paulo 

 obliquis instructi, liris spiralibus tenuioribus circa 5 supra 

 castas continuis ornati ; anfr. ultimus medio carinatus, infra 

 concavus, sublcevis ; apertura suhcircularis. 



Longit. 11 millim., diam. 3^y apertura 2g longa et lata. 



The larger costse are about twice as thick as the rest, and one in 

 number on every whorl. 



16. Odostomia (Turbonilla) fischeri. (Plate XXXV. 

 fig. 16.) 



Testa gracilis, subulata, alba, polita ; anfractus normales 9, convexi, 

 lente crescenfes, sutura subprofunda sejuncti, lo7igitudinaliter 

 confertim plicati, plicis in anfr. ultimo infra medium obsoletis ; 

 apex sinistrorsus, globosus, heliciformis ; apertura parva, longit. 

 totius ^ ad(equans ; columella subperpendicularis, vix arcuata, 

 anguste reflexa, Jiaudplicata vel contorta. 



Longit. 9 millim., lat. 2| ; apertura 2 longa, Ig lata. 



Of the two specimens under examination, one has the costae rather 

 more decidedly developed than the other. The latter exhibits slight 

 traces of spiral striae below the suture. 



17. Odostomia (Turbonilla)consanguinea. (Plate XXXV. 

 fig- 17.) 



Testa O. fischeri similis, sed gracilior, anfractibus normalihus 11 

 constructa, costis latioribus \4— 15 parum elevatis ornata ; aper- 

 tura parva, longit. totius ^ — \ adaquans. 

 Longit. 10 millim., diam. 2; apertura fere 1| longa, 1 lata. 

 The ribs or plicae in O. fischeri are about seventeen or eighteen in 

 number and considerably finer than in the present species. Besides 

 this distinction, the proportions with regard to length are so different 

 that there is little doubt that they constitute separate species. 



18. Odostomia (Turbonilla) constricta. (Plate XXXV, 

 fig. 18.) 



Testa elongata, parum pyramidalis, alba, nifida ; anfractus nor- 

 males octo, subplani, sed in medio leviter constricti, sutura lineari, 

 distincta sejuncti, costis rectis 16-17 interstitia subcequantibus, 

 instructi, anfr. ulthmis inferne Icevis, ad peripheriam. rotunda- 

 tus ; apex globosus, sinistrorsus, lav is ; apertura plus minus 

 subquadrata, longit. totius ^ sub<xquans ; columella leviter 

 obliqua, liaud torta. 



Longit. 5j millim., diam. 1 j ; apertura 1 longa, | lata. 



The constriction is just a trifle above the middle of the whorls, 

 which have a slightly turreted appearance. 



19. Solarium atkinsoni. (Plate XXXV. figs. 19-19 b.) 

 Testa discoidalis, acute carinaia, mediocriter umbilicata, albida, 



superne depresse conoidalis, lateribus leviter convexis, infra 



