NUCUUD^. 17 



tint from brownish-fulvous to pale olivej not radiatingly indented 

 anteriorly, concentrically ribbed throughout: ribs close, about as 

 broad as their narrow smooth intervals, somewhat rounded. Sides 

 equal or nearly so ; extremity of the anterior side (which, if either, 

 is the longer) a little tapering, and unsymmetrieally rounded : 

 posterior side gradually beaked, the tip acute, slightly upturned 

 below the middle. Front dorsal slope slight, plano-convex ; 

 hinder dorsal slope decided, upon the whole refuse, though a little 

 convex before the incurved termination. Ventral margin arcuated 

 and much rising in front, sirnighter and less rising behind, in- 

 dented before the base of the umbonal ridge, which latter is not 

 raised, but is sharply angulated posteriorly. Escutcheon large, 

 concave, angularly defined by the umbonal ridge, lyrated length- 

 ways throughout. Lunule (if any) smooth, linear, inconspicuous. 

 Teeth rather numerous on either side. 



29. L. Elenensis, Soirerby, f. 70-72. — T. ocquilateralis, postice 

 rostrato-acuminata, cute cinerea aliquando lutescente nonnuu- 

 quam subolivacea induta, crasse et concentriee costata. Plica 

 umbonalis eminens, subangulata, sulco inferne dilatato antice cir- 

 cumscripta. Margines dorsales subdeelives ; posticus incurvatus ; 

 ventralis postice acclivis, subsinuatus. Area impressa, ovali-acuta, 

 longitndinaliter plieato-corrugata. Lunula angustissima, trans- 

 versim porcata. — Var. (j'lhhom. T. tumida ; margine ventrali antice 

 multum arcuato, postice multum acclivi : rostro valde recurvato. 

 Var. media. T. baud tumida; rostro hand recurvato. Tar.? pi/- 

 riformis. T. oblongo-rostrata, antice valde angustata ; rostro baud 

 recurvato. — Beaked-ovale or subovate, ventricose, clothed with an 

 epidermis that ranges in tint from yellowishcinereous to olivaceous 

 ash-colonr, raved with an enlarging sulcus before the prominent 

 sub;uigular edge of the umbonal ridge, coarsely rather closely and 

 concentrically ribbed throughout (the dorsal areas excepted) ; ribs 

 erect on the umboes, depressed and shelving in front and below, 

 more or less interrupted and attenuated at the posterior fang- 

 shaped sulcus, again enlarged and very prominent on the umbonal 

 ridge: their intervals simple. Sides equal or very nearly so : front 

 extremity bluntly convex, somewhat narrowed : hinder side rostrato- 

 acuminated, gaping at the tip. Dorsal slopes rather slight or 

 moderate, the front one plano-convex : hinder one more or less 

 incurved. Ventral margin arcuated in front, straigliter and rising 

 behind, somewhat indented near the posterior end. Lunule very 

 narrow, well defined, ridged across : escutcheon rather profoui\d, 

 rather large, peaked-oval, plicately wrinkled lengthways. — Var. 

 gihbosa (Conch. 111. f. 14). Beaked-ovate, very ventricose, the 



D 



