new Mollusca from Aden. 199 



Dm-ing the past four years from Lifu alone nearly forty 

 species have come to light, described either by M. Hervier 

 or by myself in conjunction with Mr. Standen, and a more 

 exquisite series of shells could hardly be imagined, both for 

 sculpture, pattern, and colour. The species before us would 

 probably be considered a Borsonia by some authors, owing 

 to the presence of columellar plaits or teeth ; but I prefer 

 including all in Olyphostoma, as every gradation is per- 

 ceptible when the species are successively examined. 



CoralUophila arahi'ca, sp. n. (PI. XII. fig. 3.) 



C. testa globosa, solida, fere applanata, spiraliter, prtecipue apud 

 basin, leviter sulculosa ; anfractibus quinque, supernis parvis, 

 ultimo rapide accrescente, caeteros magnopere superaute ; apertura 

 alba, rotundo-ovali, nitida, intus striata, labro extus incrassato, 

 intus crenato, canali brevi. 



Long. (spec, maj.) 24, lat. 20 mm. 



A roundish, globular, thick, white species, without the 

 slightest trace of violet either in the aperture or on the 

 surface. It is closely and lightly transversely furrowed 

 towards the base of the last whorl, which is so large as almost 

 to monopolize the whole shell ; the aperture is roundly oval, 

 white, shining, striate within, outer lip thickened within, 

 crenulate at the margin, canal short. 



I think this is distinct from any form of G. violaceaj Kien., 

 = neritoidea^ Ch. ; indeed, it more resembles G. retusa^ H. & 

 A. Ad., but is of different texture, and, as before said, is 

 white, without the slightest tinge of violet, this appearing in 

 all the forms of retusa 1 have seen. 



Aclis eoccereta *, sp. n. (PI. XII. fig. 4.) 



A. testa fusiformi, versus apicem attenuata, apice vitreo ; anfracti- 

 bus undecim, paullum irregularibus, undique spiraliter delicatis- 

 sime lu'atis, quinque vel sex supernis, inclusis apicalibus, parvis, 

 sexto et septimo subito accrescentibus, tumidulis, tribus ultimis 

 rectis ; apertura ovata, labro exteriore paullum efFuso, crassi- 

 usculo, aurito. 



Long. 11, lat. 2-50 mm. 



A most graceful shell, the whorls being in the middle 

 slightly irregular. Eleven-whorlecl, of which two are apical 

 and glassy ; the sixth and seventh are tumid and more 

 swollen than the rest ; the last three are straight ; the aper- 



* f^aipfTos, choice. 



