this shell, or to the descriptions given by Lamarck of the fossil species _plicaria_, _canalifera_, and _laumontiana_, or finally, to the _Ancillaria glandiformis_, Sow. no doubt can remain of the genus _Oliva_ being here blended with the _Ancillariæ_. There is, however, another form among the _Olivæ_, which deserves mention, as it cannot well be associated with either of the preceding: this we have described below. Another genus that may be thought connected with _Oliva_, is _Terebellum_: a group very ably illustrated by Mr. G. Sowerby, in his "Genera of Shells." To that work we must refer the reader for those reasons which shew its more immediate relation to _Ovula_. It is, in short, one of those forms too hazardous to class without a complete knowledge of the animal. ---- OLIVA striata. _Shell small, cylindrical, sub-effuse, distinctly marked by regular longitudinal striæ; upper part of the body whorl with one, lower part with four, belts; spire short, channelled, sub-papillary, naked; base of the pillar striated and externally detached by a groove._ Ancillaria canalifera?? _Lam. Syst. 7, 415_. ---- We do not find this fossil clearly described. Our specimens appear to be from the London clay. Its form seems analogous to _Conohelix_ among the Mitres. The line adjoining the figures denotes the natural length of the shells. * * * * * * [Illustration: PSARIS _cristatus_. _Crested or white backed Saris._] PSARIS cristatus. _Crested, or White-backed Saris._ ---- Family Todidæ.--_Nobis._ _Bill_ lengthened, depressed, boat-shaped. _Tarsi_ moderate, weak, the three anterior toes more or less united. _Wings_ and _tail_ short. Sub-family Psariana.--_Nobis._ _Head_ very large, depressed. _Mouth_ very wide. _Bill_ thick, depressed, convex above. _Feet_ weak, tarsi rather short, toes united at their base, the outer manifestly longer than the inner; claws broad, compressed; anterior scales transverse; lateral scales small, numerous. The male generally with a spurious quill between the first and second. GENERA. PSARIS. _Cuv._ Rictus smooth, wings lengthened, the first quill much longer than the fourth, tail short, even. Type, _Psaris Cayanus_.--Cuv. PACHYRHYNCHUS. _Spix._ Rictus bearded, bill shorter, wings more rounded, tail lengthened, graduated. Type, _Psaris niger_.--Nob. ---- SPECIFIC CHARACTER. _Blackish brown, beneath pale fulvous, base of the wings with a concealed snowy spot, spurious quill broad, crown black, slightly crested._ Psaris cristatus. _Sw. in Zool. Journ. 2, p. 354._ Mus. Paris. Nost. ----