186 PLANAXIDA, 
If Mr. Smith had been able to examine as many specimens 
as I have, he would have found that none of the characters he 
relies on are constant; ¢.g., it is not smoother than many of 
the Persian Gulf specimens; the sulci are of exactly the same 
width ; and the coloration recorded is not constant. Curiously 
the typical coloration is also exactly represented by typical 
Persian Pl. breviculus. The “basal canal” likewise is often, 
if not generally, entirely like that of its allies ! 
The habitat is very interesting, being the only one known 
East of the Bay of Bengal: it is particularly important to find 
the species actually living with Pl. sulcatus. The fig. of Pl. 
encausticus in the Con. Iconica is very fair, but fig. 30, a “ Pl, 
savignyi,” has the last whorl less tumid than is usually the 
case. 
8. Planaxis breviculus. 
Planaxis breviculus, Deshayes, Mag. Zool. 1844, Hab. ?, long. 21, diam. 15 
mil. ; Suez, “frequent,” fide McAndrew. 
4 Persian Gulf; coll, W. T. Blanford, Esq. [19, 134]. 
Coloration close to that of the original figure, also to that 
of the Arakanese Pl. savignyi, var. encaustica. Pl. breviculus 
is scarcely more than a well-marked variety of Pl. savignyi ? 
The darker-coloured aperture, however, with obsolete liration, 
seems to be characteristic. 
var. tessellata, nov. 
Pil. breviculus, var., Smith, Ann. Mag. IX, 1872, Persian Gulf. 
20 Persian Gulf; coll. W. T. Blanford, Esq. [long. 20, diam. 14]. 
Both these and the preceding have a more acuminate spire 
than in the figure of Deshayes. The figure in Con. Iconica 
seems to me different again; possibly it represents Pl. brevis, 
Quoy, as Sowerby quotes the latter’s localities—“‘ Guam and N. 
Guinea” —for the figure in question, 
4. Planaxis planicostatus. 
Planaxis planicostatus, Sowerby, App. Tankerv. Cat. 1825, Gallapagos I. ; 
fide Smith=Bue. planawvis, Wood; =Pl. canaliculata, Duval, Rev. 
Zool. Cuv. 1840 ; = Pl. circinata, Lesson, Rev. Zool. Cuv. 1842, “ Aca- 
puleo 0-020.” 
5 Panama; ex c. Prof. EB. C. Stearns and Asiatic Soc. Bengal [28, 16]. 
