Our drawing, scrupulously exact, was made at the _Jardin des Plants_. As we find _Nyctinomus_ is a name already appropriated, we have substituted _Nyctiornis_: and we place this group at the extremity of the _Fissirostres_, adjoining to _Prionites_ among the _Scansores_. Total length ab. 13, wings 5¼, tail (beyond,) 3, tarsi hardly ½ in. * * * * * * [Illustration: CULICIVORA _atricapilla_. _Black-crowned Gnatcatcher._] CULICIVORA atricapilla. _Black crowned Warbler._ ---- Family, Sylviadæ. Sub-family, Sylvianæ. _Nob._ (_See North Zool. Vol. 2._) GENERIC CHARACTER. CULICIVORA. _Swains. in Zool. Journ. No. 11. Lesson Man. 2. p. 430._ _Bill_ very slender, the base depressed, the sides compressed, the culmen arched from the base. _Nostrils_ long; aperture linear and naked; rictus bearded. _Wings_ remarkably short. _Tail_ slender, graduated, and generally lengthened. ---- SPECIFIC CHARACTER. _Above cinereous, beneath white; upper part of the head, middle tail feathers, and base of the three outer feathers deep black. Quills blackish, with white and grey margins._ Figuier à tête noir de Cayenne? _Pl. Enl. pl. 704. f. 1.?_ ---- The birds composing this natural but intricate group, have hitherto been found only in America. Scarcely superior in size to the Gold-crested Wrens, they exhibit much of the same activity and restlessness in searching after insects. Yet their manners, in other respects, are more in unison with those of the flycatching birds. In size and in structure, our bird perfectly accords with the _Sylvia cærulea_ of Vieil, and represents that northern species in tropical America, but we are fearful of identifying it with that figured in the _Pl. Enl._ Our drawings are of the natural size; in both these species the bill perfectly resembles that of _Prinia_. Horsf. except in being somewhat shorter: the feet, however, are those of _Setophaga_, Swains. The Flycatchers and Warblers, are so blended together, by all writers, that we have not yet been able to discover the typical example of this group. Its true affinities, however, appear to be as follows:-- _Culicivora_ is represented in Africa by _Drymoica, Sw._, in India by _Prinia, Horsf._, and in Australia by _Malurus, Vieil._ These genera, in conjunction with that of _Sylvia_, seem to indicate the first typical circle of this family. Culicivora exhibits many singular characters; in some approaching to _Prinia_, the tail is very short: others, shewing an affinity to _Sylvia_, have yellow crests: while a few species, leading to _Setophaga_, present us with the depressed bill of a Flycatcher. * * * * * * [Illustration: OLIVA. Pl. 2. _Olivella purpurata. 2. eburnea._] OLIVA purpurata. _Purple-mouthed Olive._ ---- Family Volutidæ.--Genus Oliva. _Auct._ SUB-GENUS, OLIVELLA. CHARACTERS.