230 JOURNAL OF CONCMOLOGY, VOL. I4, NO. 8, OCTOBER, I914. 



Var. 2. lissostoma Smith (fig. 3). 



The second variety is that figured by Reeve\ Tryoir, Kiener^ and 

 Kobelt'', and may be known from the preceding form by its longer 

 aperture, ahnost smooth columella, and the absence of the Urge with- 

 in the mouth. It has the twelve tubercular liras on the labrum, but 

 not those further within. The edge of the columella, and the aperture 

 within the whitish or flesh-coloured labrum are generally of a deep or 

 bright red. 



Length of an average specimen about no mm., of a larger specimen 

 150 mm. 



Hab.— Indian Ocean, Madagascar, Red Sea (Kiener). 



I regret to say that I cannot state any certain localities for this 

 variety. It is quite separable at a glance from the preceding form. 

 Can the differences indicated possibly be sexual ? 



Var. 3. gigantea Smith (figs. 4, 5). 



The third variety grows to an enormous size, and is that form (fig. 

 4.) figured by Reeve^, and perhaps by Chemnitz^ The aperture with- 

 in is either white or fleshy orange, and the columella is transversely 

 finely Urate above the middle, and more strongly below. The labrum 

 in adult examples is broadly expanded, dentate at the edge, and very 

 faintly ridged within, the ridges corresponding to the denticles (gener- 

 ally brown) on the margin. Usually there are one or two denticles 

 posteriorly, opposite a strong lira at the upper part of the columella. 



In a young example of this variety the faint ridges within the 

 labrum take the form of distinct elongate tubercles as in variety i. 



Two enormous specimens from Muscat (fig. 5) on the Arabian 

 Coast, Gulf of Oman, may be placed in this variety although they 

 appear to have less of the tubercular sculpture shown in Reeve's 

 figure. One of these has the aperture, columella callus, and labrum 

 entirely white, but in the other these parts are of a flesh tint. 



The larger specimen is 360 mm. in length and weighs 4 lbs. 6 oz., 

 whereas an apparently full-grown example of var. i weighs only 4 oz., 

 but I should state at the same time that an apparently adult specimen 

 of this third variety weighs but 10 oz. 



Chemnitz (Conch. Cab. vol. iv., p. 87) states that he had a 

 specimen from Mauritius or Bourbon in his collection, 14 inches long, 

 and that Spengler had still larger examples. 



The contrast between var. i and these gigantic specimens is so 

 great, that at first sight it seems ridiculous to consider them forms 



1 Conch. Icon. voL ii , pi. x, fig. 30b. 



2 Man. Conch, vol. iii., pi. xi.\, fig. 12, copy of Reeve. 



3 Coq. Viv. pi. V, fig. I. 



4 Illustr. Conchylienbuch, pi. ix., fig. 2. 



5 Conch. Icon. vol. ii., pi. ix, fig. 30a. 



6 Conch. Cab. vol. iv., fig. 123S. 



