Mollusca of the Arabian Sea, &c. 83 



described in this paper, to a MactrinuJa, a Lucina, and Gryp- 

 todon victorialis, all three of unusual delicacy. In Gastro- 

 poda a fine Fusus, two Mitrce, a beautiful Naiica, and a 

 Lacuna, the second of a northern genus to be described 

 from tropical seas, are, perhaps, the most noteworthy. 

 But there still are more Pleurotoraidge in proportion to other 

 orders represented ; indeed it is both curious and deeply 

 interesting to observe how much that is fresh this highly 

 organized assemblage of mollusks continues yearly to afford 

 from all parts of the world and at all depths. One of our 

 greatest desiderata is, and I fear may long continue to be, 

 an up-to-date monograph of this group, fossil as well as recent, 

 for it seems to me that certain Dn'llice, Clathurelice, and 

 Mavgilice, especially, of the Tertiary formation run very close 

 to, if they are not absolutely identical with, similar existing 

 forms. 



Fusus Townsendi, sp. n. (PI. II. fig. 1.) 



F. testa eleganter fusiformi, usque apicem rapide attenuata, cinerea, 

 nifo-vel brunneo-porpureosuttusa; anfractibus 11, duobus apicali- 

 bns globulosis, vitrifactis, ochraceis vel brunneis inclusis, cseteris 

 apud suturas miiltum impressis, longitudiualiter costatis, costis 

 fortibus, crassis, ad medium acuticarinatis, et fusco-pictis, ultimo 

 in anfractu ad nuraerum iiovem, superficie tota spiraliter arete 

 filo-lirata, ad medium anfractuum perforti, interstitiis tenui- 

 liratis ; apertiira oblonga, intus ciuerea, striata ; canali perlongo 

 (ad 32 mm.), arete lirato usque ad basim ; labio tenui ; columella 

 nitida, paullnm reflexa. 



Long. 80, lat. 24 mm. (sp, maj.). 

 „ 60, „ 19 „ (sp. miu.). 



Hab. Persian Gulf, dredged at 10-12 fathoms, in sand and 

 mudjOfFGais (or Kais), Hinderabi, and Sheik Shuaib Isles. 



A fine species, with a resemblance to F. tuberculatus, 

 Lamk., or toreuma, Mart., in miniature. Many examples 

 were forwarded by Mr. Townsend, neaidy all, even the most 

 juvenile, covered, especially towards the apex, with Lepralia. 

 Unlike tuberculatus, the dark coloration is on the ribs, not at 

 the interstices. The colour varies from ochreous or stra- 

 mineous to purplish brown on a grey ground ; the whorls are 

 eleven in number, two being apical and glassy brown, the 

 rest are very strongly ribbed, all acutely angled in the middle 

 of each whorl, the ribs showing here most prominently, 

 with narrow white spaces surrounded by a dark brown 

 coloration. The spiral liree are very close and fine. Canal 

 much produced ; aperture oblong j mouth greyish within and 



6* 



