400 Mr. W. T. Blanford on Fairbankia bombayana. 
examine it more closely in connexion with the estuarine 
Rissoid genus Jravadia, and I then found that the present 
form showed distinctions not only from issoa proper, but also 
from all the other genera of Rissoide 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 verticali 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 Rissoide, 
and approaches that of Hissoella. 
From Rissoa the present genus is distinguished by its thick 
epidermis, straight smooth columella, and by the characters of 
the operculum,—trom Barleeta, to which Dr. Stoliczka (Pa- 
leontologia 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 of Bar/leeia 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 Jravadia (Journ. As. Soc. Bengal for 1867, vol. 
Xxxvi. pt. 2. p. 56), 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 incrementi minute decussata, epider- 
mide fusco-olivacea induta. Spira lateribus convexiusculis, apice 
papillari, interdum erosulo, sutura impressa. Anfr. 7, convexi, 
ultimus subtus rotundatus. Apertura subovata, postice angulata; 
peristomatis marginibus conjunctis, externo mediocriter expanso, 
