144 TROPHON. 



The aperture, in this species, as well as in the related T. Gever- 

 sianus and T. xanthosloma, being very wide, a modification of 

 the form of the operculum occurs, in a lateral growth from the 

 initial point, which causes the latter to appear as if on the outer 

 side instead of the lower extremity, simulating the Purpuroid 

 operculum. T very much doubt whether these Southern Ameri- 

 can and New Zealand species really belong to Trophon, but am 

 not prepared to give them any other position at present. 



T. GEVERSIANUS, Pallas. PL 3*2, tigs. 337-347 ; PL 70, tigs. 

 433, 435. 



Typically, this species is broad ovate, shouldered, with numer- 

 ous frill-like varices and elevated, rounded, revolving ribs; um- 

 bilicus widely exposed, aperture chestnut within. 



Length, 2'5 to 3 inches. 



Magellan's Straits to Chili. 



With this typical form must be united Murex Patagonicus, 

 d'Orb. (fig. 340). This author has described a much heavier 

 shell, round shouldered, without varices, under the name of M. 

 varians (figs. 346, 348), although suspecting it to be the same as 

 Geversianus. Gray considers it the same, and I think there is 

 no doubt of it, as I have before me intermediate forms, among 

 which are vars. calva (fig. 338) and lirata (fig. 347) of Kobelt. 

 Then there is a smaller form called Philippianus, Dunker (fig. 

 343), which I figure. This may be considered a variety. Fuxu* 

 intermedium, Gay (PL 70, fig. 433) is another variety. Fusus 

 decolor, Phil. (fig. 342), is founded on worn specimens of var. 

 Philippianuit, Dunker. I think F. albidus Phil. (341). is also this 

 variety. T. albolabratus, K. A. Smith (PL 70, fig. 435). from 

 Kerguelen's Island is said to differ from T. Philippianux in the 

 whorls being more rounded above, the penultimate whorl is larger 

 and more elevated ; body-whorl more inflated below the middle, 

 not prolonged into such an elongated cauda ; the aperture rather 

 larger, longitudinal lamellae more prominent and not nearly so 

 numerous. Long. 40 mill., diam. 18 mill. 



It is a narrower shell than any of those quoted above, and 

 may be distinct, but I doubt it. 



