LIGUUS CORONA. 179 



last whorl; several earlier whorls with wedge- shaped or irregular purplish 

 longitudinal streaks. Aperture white and thickened inside, the lip 

 with a black-brown edge and border within ; col umella chestnut col- 

 ored, short, with a particularly heavy and convex fold directed in- 

 wardly ; the parietal callus black. 



Alt. 61, diam. 29, longest axis of aperture 29-^ mill.; whorls 7J. 



Demerara (Jacobs, in R. Swift coll.). 



Achatinia perversa SWAINSON, Zoological Illustrations i, pi. 36 

 (1820-21) Helix regina, monstrum, sinistra, FERUSSAC, Histoire, 

 pi. 119, f. 6. Orthalicus rex, b. sinistrorsus, BECK, Index Moll., p. 

 60 (1837). 



Bidimus regina d'Orb., HUPE in Castelnau's Exped. dans 1'Amer. 

 du Sud, p. 33, pi. 10, f. 2 ; pi. 7, f. 1, la. 



The blackish edge and internal border of the peristome, the 

 shortness of the very convex and deeply situated columellar fold, and 

 usual absence of basal truncation, the more pronounced effuseness or 

 retraction of the base of the aperture, are all characteristic features 

 of this form as contrasted with those following. The peripheral band 

 and occasional black varices are also conspicuous, and with the bold 

 longitudinal blotches and partial or complete obsolescence of a me- 

 dian articulated band on the whorls of the spire, usually permit ready 

 recognition. In large specimens, however, the peripheral belt may 

 become inconspicuous. 



Hupe's "Bidimus regina 1 ' (pi. 36, figs. 24, 25) is apparently refer- 

 able to this species as a dextral form, rather than to the typical 

 regina; but it is not far from being a transition form between the 

 two. 



Swainson's name perversa was doubtless properly published before 

 Ferussac's regina, and was not pre-occupied ; so that should the two 

 be consolidated as the result of further investigations, L. perversus 

 will take precedence. Swainson's type was a specimen almost ex- 

 actly like my figs. 20, 21, 22 in size and coloration. 



L. INCISUS (Hupe). PI. 35, figs. 15, 16, 17. 



Shell sinislral, elongate-turreted, irregularly wrinkled by longitu- 

 dinal striae ; spire pyramidally acuminate, the apex obtuse ; whorls 

 somewhat convex ; chestnut-brown, with longitudinal flexuous or 

 angulated flammules, and an articulated band in the middle of the 

 whorls of the spire, and when present, above the middle on the last 



