134 AMERICAN JOURNAL 



on the last whorl; labium •witli the callus diffused; labrum with 

 its margin erect, with six moderate digitations, and with the 

 antesinual lobe little undulated. Lips whitish or lurid. 



Hab. — Society Islands. 



B. Aperture corrugated within. { 3Iillipe 8, MUrch, Ad. f.) 

 1. Digitations of labrum six, between the median of which 

 are dentiform processes. 



4, P. scoRPius, Lam. ex Linn. 



Strombus seorpius, Linn., Sjst. Nat. ed. 12, p. 1208. 

 Pterocera nodosa, Encycl., pi. 410, f. 2. Swains., Exotic 



Conch. App. p. 32. 

 Pterocera scorpio, Lam., Hist. Nat. An. sans Vert. ed. 2, ix, 



p. 674. 

 Pterocera seorpius, Reeve, Mon. Pterocera, sp. 3. 

 Pterocera (^Millipes) scorpio, Morch, Cat. Yoldi, p. 60. 

 Millipes scorpio. Ad. f. Gen. Moll, i, p. 261. 

 Pterocera [Millipes) scorpio, Gicxhh, Am. Journ. Conch, iv, p. 



140. 



Labrum with a prominent transverse white ridge in front of 

 the concavity of the dorsal tubercle ; laterally inflected, ribbed 

 between the spines, and with a dentated margin ; the spines no- 

 dose, and the posterior furnished with a compressed auriform lobe 

 at the left base. 



Hob. — Philippine Islands, 

 5. P. PSEUDOSCORPio, Lam. 



Pterocera pseudo-scorpio, Lam,, Hist. Nat. An. sans Vert. ed. 



2, ix, p. 674. Reeve, Mon. Ptcsrocera, sp. 4. 

 Pterocera i^Harpago) pseudoscorpio, Morch, Cat, Yoldi, p. 60. 

 Millipes pseudoscorpio. Ad. f. Gen. Moll, i, p. 261. 



Labrum with no distinct ridge behind, and with the concavity 

 of ihe tuberele mostly in advance of the columellar fold ; mode- 

 rately inflected, with single dentiform lobes between the angular 

 and median, and median and postsinual spines ; with spines obso- 

 letely or not at all nodose, and the posterior simple and with no 

 basal lobe. 



Hab. — Zanzibar, etc. 



This very distinct species has hitherto only been distiuguished 

 from P. scorjnus by the larger size and larger and less nodose 

 spines, and consequently it was natural that Reeve and others 

 should have been of the opinion that " it is extremely doubtful 



