It is the animal of this genus of Shells, which in sickness and disease, produces the true oriental Pearl: the costly ornament of sovereigns, and the chaste foil of beauty. An interesting account of the Pearl fishery of Ceylon, will be found in Mr. Wood's entertaining _Zoography_, extracted from Percival's History of that island. The present is a small species, seldom exceeding the size of the figure: in young shells there is a cardinal tubercle in our valve, which disappears with age. The Pearl-oysters are nearly all inhabitants of warm seas; the species require much elucidation. The genera, above enumerated, appear to present such a series of affinities, as to justify our suspicions that they form a natural group: the more so, as their analogies may be traced among the perlacious fluviatile shells, forming our family _Unionidæ_. If further investigation should confirm the correctness of this idea, the sub-genera will, of course, become types of form; bearing the same relation to the genera, as _Dipsus_ does to _Anodon_, or _Castalia_ to _Hyria_. * * * * * * [Illustration: NYCTINOMUS _amictus_. _Duvaucel's Nightfeeder._] NYCTIORNIS amictus. _Duvaucel's Nightfeeder._ ---- Sub-order, Fissirostres. Family ----? GENERIC CHARACTER. _Bill_ subfalcated, compressed, margins of the upper mandible folding over those of the lower: _rictus_ excessively wide. _Wings_ rounded, moderate. Plumage lax, long. _Tarsi_ much shorter than the hallux. _Toes_ and claws as in _Merops_ and _Prionites_. _Nobis._ ---- SPECIFIC CHARACTER. _Green, crown (in the adult) lilach, front of the throat and breast bright red._ Merops amictus. _Pl. Col. pl. 310. fig. pessima._ Mus. Paris. ---- This is perhaps the rarest, and certainly the most extraordinary bird, which the recent Zoological researches in India has brought to light. Its discovery is due to a young and accomplished Naturalist of France--M. Duvaucel, now alas! no more: but who lived to perpetuate his name by his brilliant discoveries, and to enrich the French Museum with the most splendid specimens of oriential Zoology now in Europe. The form, habit, and wings of this charming bird, are almost precisely those of _Prionites_; while the bill resembles that of _Merops_. Nothing can exceed the beauty of its lilach crown, or the bright vermillion of its throat. The bill is strong, and marked above on each sides with a sulcated line: the gape is so wide, as to reach underneath the eye. The whole structure of the bird, its round wings, and long lax plumage, indicates a totally different economy from that of _Merops_; and this has been confirmed by Sir W. Jardine and Mr. Selby, who inform us that another beautiful species, they have described, _feeds during the night_.