SCALID^ OP THE WEST INDIA ISLANDS. 193 



3. ScALA PRINCIPALIS, Pallas. 

 T. obtecte perforata, ovato-turrita, tenuiuscula, Candida, nitidiila, snb lente obsoletissime irregu- 

 lanter spiraliter striata; anfr. x disjuncta, costis xiv regiilaribus acutis in anfr. ult.; apertura 

 oblique ovalis, labio reetinsculo. 

 Long. 36 mm.; diam. 16 mm.; alt. aperturse 10 mm. 



Turho principalis, Pallas, Spic. x, 1774, p. 32. 



Naturg. merckwiird. Thiere. x. 1778, p. 51, t. 3, f. 3, 6. 

 Angarius scalaris seu var. rarissima, Meuschen Mus.Gevevs. 17H7, p. 260, n. 203. 

 Die seltene enge geribbte Wendeltreppe, Martini, Berlin, Samml. Bd. vii. p. 28, 



tab. tit. 

 Ticrbo principalis, Chem. iv. p. 273, f. 1128, 29. 



" Schroter Journal, ii. p. 451. 



Hab. Tortola, spm. unicum (A. H. Riise). 



Scalaria principalis, Sovvb., Thes. fig. 75, p. 88, n. 23, from Xipixapi, is different. 

 Scala ducalis, Morch. 



Scala costulata, Kien. Spec. Gen. differs chiefly in having the ribs more 

 numerous and lower. 



I am not aware that this species is found in any collection but that of Mr. 

 Eiise, now in Copenhagen, 



4. Scala swiftii, Morch, n, sp., PI. 29, fig. 3. 



T. aeuminato-ovata, vix perforata, alba, polita, lineis aciculatis, spiralibus, obsoletissimis ; anfr 

 disjuncti, convexi vii-viii, sutura rimata; costse foliacese in anfr. ult. xii, pagina antica obso- 

 letissime rugoso-granulosa; apertura ovata, abbreviata, antice effusa, labio subtorto. 

 Long. 14 mm.; diam. 9 mm.; alt. aperturae 5 mm. 



Hob. St. Thomas (R. Swift), spm. unicum. 



'"''Scalaria bulbulus, Sowb.," Coll. Swift. 



Scala obtusa, Sowb., is the species nearest allied. The aperture is effuse, like 

 that of Melania; the ribs of the last whorl touch the front side of the correspond- 

 ing ribs of the preceding whorl. 



5. Scala novemcostata, Morch, n. sp. 



T. abbreviato-turrita, imperforata, alba, nitida, tenuiuscula; anfr. disjuncti, convexi, rima angus- 

 tissiraa ; costas compressse, acutse, altissimse, continuse, in anfr. ult. ix. Apertura suborbicu- 

 laris, obsolete coarctata. 

 Long. 9 mm. ; diam. 4^ mm. ; alt. aperturae 2 mm. 



Hab. St. Thomas (Riise), spm. unicum. 



Scala heocagona, Sowb., and epecially Scala foliacea, Sowb., from the Crag 

 formation, are nearly allied to this species. 

 49 



