400 Mr. W. T. Blanford on Fairbankia bombayana. 



examine it more closely in connexion with the estuarine 

 Rissoid genus Iravadia, and I then found that the present 

 form showed distinctions not only from Rissoa proper, but also 

 from all the other genera of Rissoidse previously described. 



Fairbankia, nov. gen. 



Animal tentaculis longis filiformibus ; oculis ad basin tentaculorum 

 sessilibus ; proboscide elongata ; pede antice lato, sinuato, postice 

 rotundato. 



Testa imperforata, turrita, epidermide fusca induta ; apertura sub- 

 ovali, antice rotundata ; peristomate leviter dilatato, margine ex- 

 terno acuto, sed extus variciformi-incrassato. Operculum cor- 

 neum, subovale, subannulare ; nucleo excentrico, juxta medium 

 lateris columellaris posito, intus costa elongata vertieali munitum. 



This genus combines the epidermis and, to a great extent, 

 the animal of Hydrobia with the peristome of a Rissoa^ while 

 the operculum differs from that of any other of the E-issoidse, 

 and approaches that of Rissoella. 



From Rissoa the present genus is distinguished by its thick 

 epideiTuis, straight smooth columella, and by the characters of 

 the operculum, — from Barleeia^ to which Dr. Stoliczka (Pa- 

 laeontologia Indica, v. p. 274) considers it very nearly allied, 

 by its epidermis, its externally thickened peristome, by its 

 operculum being horny and devoid of any long pointed apo- 

 physis (both genera have an internal raised rib), and by se- 

 veral distinctions in the form of the animal, such as the pos- 

 session of long filiform tentacles, whilst those oi Barleeia are 

 described as short, broad, and rounded at the tips. From 

 Hydrobia the operculum and thickened peristome amply dis- 

 tinguish the present genus. 



On the whole, I am myself strongly disposed to believe 

 that the most closely allied genus is that which I described 

 recently as Iravadia (Joum. As. Soc. Bengal for 1867, vol. 

 xxxvi. pt. 2. p. 6Qt)y from the estuary of the Irawady River. 

 The operculum and animal of that genus are unknown : the 

 shell possesses an epidermis, and has an external varix to the 

 peristome ; but the whorls are deeply sulcated, and the aper- 

 ture is effuse in front, showing some approximation in form to 

 that of Rissoina. 



Fairbankia bombayana^ n. sp. 



Testa imperforata, non rimata, turrita, solidula, albida, lineis con- 

 fertis spiralibus striisque increment! minute decussata, epider- 

 mide fusco-olivacea induta. Spira lateribus convexiusculis, apice 

 papillari, interdum erosulo, sutura impressa. Anfr. 7, convexi, 

 idtimus subtus rotundatus. Apertura subovata, postice angulata ; 

 peristomatis marginibus conjunctis, externo mcdiocriter expanse, 



