MELVILL : MOLLUSCA FKOM PERSIAN GULF, ETC. 245 



RissoA (Amphithalamus) dknsilabrum, n.sp. PI. XII, Figs. 8, 8a. 



II. testa parva, solidula, pallide straniinea vel cinereo albescente, 

 imperforata, ant'ractibus •^^, quorum 2^ apicales, apice ipso depresso, 

 secundo aut'raotii vitreo, globoso, caeteris ad suturas pauUuin impressis, 

 uiidique spiialiter arete liratis, liris pro parte crassiusculis, interstitiis 

 sub lente iuterdum plauatis, interduni subalveolatis, apertura ovata 

 regioue labrali dorsaliter iucrassata, labro fere contiuuo, columella 

 obliqua, ad basim crassiore. Long. 2*75, lat. 1*25 mm. 



Ilab. — Karachi. 



A small Rissoid, which we refer to AmpJi I thalamus, Carp. (^ = Scrobs, 

 Wats.), tliougli there are leanings towards the section Onoba, 

 H. & A. Ad. The transverse lirse are close and coarse for the size 

 of the shell, the region of tlie outer lip being, dorsally, considerably 

 thickened and incrassate. The species occurs generally, but locally, 

 along the Mekran Coast, but more particularly in the neighbourhood 

 of Karachi, but I cannot find that it has been described previously. 



IlissoiNA TiBiCEN, n.sp. PI. XII, Fig. 9. 



E.. testa attenuato-fusiformi, apud basim latiore, nitida, solidula, 

 Ifievi, alba, aufractibus 9, quorum apicales 2^, perlfcves, subpellucidi, 

 bulbosi, cseteris longitudinaliter laevicostatis, costis anfractus ultimi 

 9-10, usque ad basim ipsam extensis, superficie interstitiali sub lente 

 uudiipie spiraliter teuuissime sti'iata, apertura rotundo-ovata, peristo- 

 mate incrassato, albo, nitido, columella paullum excavata. Long. 5"75, 

 lat. 1'75 mm. 



Hab. — Persian Gulf, Mussandam, 55 fathoms. 



This select, white, shining, somewhat pellucid Hissoma, belonging 

 to the typical section of the genus, is somewhat isosceles-sha])ed, 

 attenuately fusiform, neatly and smoothly ribbed, the interstitial 

 spaces with a high power appearing uniformly spirallj' striolate. 

 It may, perhaps, be compared in form with Ji. te)-ebra, Garrett, from 

 Fiji, but the character of the ribs, ornamentation, etc., is altogether 

 diverse. Except for size this species is much like the type of the 

 genus Stita,^ Hedley, but S. ferriiginea is 18 mm. in length, from 

 Wol 1 on gon g, A u stralia. 



(Tibicen, a piper.) 



FOSSAEUS APTTJS, D.sp. PI. XII, Fig. 7. 



F. testa ovato-rotunda, conica, albo-straminea, delicata, anguste sed 

 profunde umbilicata, aufractibus 5, quorum apicales 2 castanei, parvi, 

 siiiiplices, cpeteris gradatulis, penultimo spiraliter tri-, ultimo quinque 

 carinulato, interstitiis spiraliter teuuistriatis, apertura lunulata, 

 intus pallide straminea, labro tenui ; extus 6-denticulata, margine 

 columellari margine fere recto. Alt. 3, diam. 3 mm. 



Ilab. — Persian Gulf, Mussandam, 55 fathoms. 



A very small species, with elaborate sculpture, as above described, 

 5-keeled spirally on the body-whorl, with fine spiral intermediate 



1 Proc. Linn. See. N.S. Wales, 1904, p. 192, pi. ix, figs. 23-5. 



