OF SOUTnERN IXDIA. 259 



specimens very strongly dentated and thickened. I liave only imperfectly seen 

 tlie hinge-teeth, the cardinals appear to be regular, the posterior are very much 

 smaller than the anterior ; on each side there is a long lateral rim parallel to the 

 margin, as in other Liicina;, hut whether it terminates with a sjjecial lateral tooth 

 I have not been able to trace out. 



Localities. — Olapaudy and west of Arrialoor, in a brownish and gi-ey conglo- 

 meratic sandstone. 



Formation. — Ai-rialoor group. 



XXIV. Family,— UNG VLINIDjE. 



The animals of the genera referable to this family agree in form with those of 

 the LuciyiDM, but they have the mantle margins much more united below, leavino- 

 in front only a comparatively small pedal opening, the siphonal orifice is also single ; 

 the gills are of moderate size and consist of two elongated plumes on eacli side ; 

 the foot is elongated, hollow inside, generally vermiform, or somewhat geniculate, 

 but always much shorter than in the previous family ; the mouth is of moderate 

 size, and the palpi, four in number, well developed. 



The shells arc oval or roundish, rather thin, with the internal surface always 

 of a peculiar silky or pearly appearance and mostly quite smooth ; the hinge usuallv 

 has two small cardinal teeth in each valve, the laterals are always wantino- ; the 

 muscular scars are oval, or elongately oval, sub-equal, the anterior bein"- rarelv 

 much longer than the posterior ; pallial line entire, sometimes truncate posteriorly 

 and generally faint ; ligament external or sub-internal. 



I shall refer to this family the following seven genera : ITiiipagus, Scacchia, 

 Ungulina, Cyrenoida f=C>/renellaJ, Felania, Mijsia (=Biploclonta), and Fsatlmra. 

 Deshayes, and many other conchologists wdio accept that celebrated author's 

 views, class several of the above-named genera in the Lvcinidm, admittino- the 

 difficulty which exists in the classification of the fossil species. There can be no 

 question that all those genera quoted exhibit a very marked relation to the Xzjcav/z)^; 

 but when we look at the important differences which I have pointed out in the 

 anatomy of the animals, namely, the small size of the foot, the presence of well 

 developed labial palps, the single posterior siphonal orifice, and also the reo-ular 

 want of lateral teeth in the shells, their thin and silky internal structure, the form 

 of the muscular impressions, &c., we must regard the present family, in the manner 

 introduced by H. and A. Adams in their " Genera," as a small natural group of 

 shells. 



In their geological history the Vkovlinidje also differ somewhat from the 

 LvcmiBM. There are some forms known already in paltcozoic (Silurian and 

 Carboniferous) rocks, very strongly resembling in external shape TJiigidina, and 

 which have been described under that generic name ; but sufficiently authenticated 

 species of the family are as yet only on record from cretaceous and younger 

 deposits, theii" number slightly increasing up to the present date. On the whole, 

 these shells are always rare. 



3 s 



