184 BULLETIN OF THE 



Orbigny, and N. ambigua Montagu, llyanassa obsoleta Say, confined to the 

 continental shore and noc reaching the southernmost extreme of Florida, and 

 an undescribed species mentioned later, make up the list. The deep-water 

 Nassa nigrolabra of Verrill has not turned up in these waters yet, and I doubt 

 the propriety of referring it to this genus. Indeed, it has, judging from the 

 figure, the appearance of a larval shell, though without examining a specimen 

 I would lay no stress on this suggestion. Its smooth unsulcate pillar, however, 

 removes it from the genus Nassa, if it is adequately figured. 



Nassa ambigua Montagu. 



Buccinum ambiguum Mont., Brit. Test., pi. ix. fig. 7, 1803. 



Nassa alba Say, Journ. Acad. Nat. Sci. Phil., V. p. 212, 1826. 



Nassa antillarum Orbigny (not Philippi), Moll. Cuba, II. p. 141, pi. xxiii. figs. 1-3 



1815 (dark variety). 

 Nassa ambigua Orbigny, Moll. Cuba, II. p. 142. 



Nassa Candei Orbigny, op. cit., p. 142, pi. xxiii. figs. 4-6, 1845 (voung shell). 

 Nassa candidissima C. B. Adams, Krebs, Cat. p. 32. 

 1 Nassa obtusata Marrat, Argo Exp., pp. 16, 17, 1876 (not of A. Adams, an E. Indian 



species). 

 1 Nassa incrassata Guppy, Geol. Mag., p. 447, 1874 (not of Strom, a European 



species). 

 1 Nassa pura Marrat, New Forms of Nassa, p. 13, 1877. 

 Nassa annellifera Reeve, Conch. Icon. Nassa, pi. xxv. fig. 168, 1853 ; Marrat, Argo 



Exp. p. 8. 

 Not N. ambigua Dunker, W. Africa, = N. incrassata Strom. 



Habitat. Yucatan Strait, 640 fms.; Station 2, 805 fms.; Barbados, 76-103 

 fms., including Stations 273 and 276; Station 142, Flannegan Passage, in 27 

 fms.; Station 155, off Montserrat, in 88 fins.; Station 210, near Martinique, 

 in 191 fms.; off Sombrero, in 54 fms.; Sigsbee, off Havana, in 80 and 177 fms.; 

 Bahamas; Bermuda; Dominica; Florida, Lower Matacumba Key, in grass 

 below low-water mark (Hemphill); Key West, Goodland Point, and other 

 localities in Florida from low water to 2 fms. (Hemphill).  



The shells dredged by the Blake were all dead, and most of them occupied 

 by Paguri ; none of them probably lived below a depth of a few fathoms, above 

 which it would seem that this must be one of the most abundant and widely 

 spread of the Antillean species. 



This is the commonest littoral species of Nassa, and its varieties have received 

 many names. It has a different nucleus from the very similar N. incrassata 

 of Europe and "West Africa. It varies in the number of its ribs, their angula- 

 tion in front of the suture, in being white or banded or speckled with brown, 

 and in the strength of its spiral threads. The typical ambigua has numerous 

 rounded ribs, not angulated, and evenly reticulated. The variety antillarum 

 has the ribs fewer and stronger, and with a marked angulation which tur- 

 riculates the whorls. 



