Zoological Illustrations Volume I Part 24

In general size it is rather larger than the Brazilian Toucan. Our figure is on the exact scale of four-tenths to an inch. Its precise locality I am unacquainted with. We hope to enlarge more on this interesting genus in another publication.

Pl. 57

[Ill.u.s.tration]

UNIO nasutus.

_Rostrated River-Mussel._

GENERIC CHARACTER.

_Testa transversa, aequivalvis, non affixa; natibus decorticatis, suberosis; impressio muscularis postica composita. Dens cardinalis unicus, brevis, irregularis, simplex aut bipart.i.tus, substriatus; dentes laterales duo, elongati, compressi, infra p.u.b.em producti._

Typus Genericus _Mya Pictorum_. Linn.

Sh.e.l.l transverse, equivalve, not affixed, the tops decorticated.

Posterior muscular depressions double. Cardinal tooth one, short, irregular, simple or double, striated; lateral teeth two, elongated, compressed, and prolonged beneath the corslet.

Generic Type _Mya Pictorum_. Linn.

SPECIFIC CHARACTER.

_U. (Div. 2.) testa transversim elongata, margine dorsi recta, antice angulata oblique attenuata, extremitate subtruncata._

Unio (Div. 2.). Sh.e.l.l transversely elongated: dorsal margin straight; anterior side angulated, obliquely attenuated, the extremity slightly truncated.

_Lister, tab._ 151. _fig._ 6.

Unio nasutus. _Say in Encycl. Am. Conch. pl._ iv. _fig._ 1.

This is one of the most natural genera in the modern systems of conchology, as it includes all fresh-water bivalves having two rough cardinal teeth in one valve and one in the other. The colours of all are more or less dark-brown, sometimes radiated with green; but the specific characters rest on the contour of the sh.e.l.l and the proportion of the teeth.

There can be no doubt this sh.e.l.l is the _Unio nasutus_ of Say, who refers to the figure of Lister. The _Unio nasuta_ however of Lamarck I apprehend will be found different, as he seems to think; his sh.e.l.l also is purple inside with short thick teeth; indeed so much uncertainty hangs on the sh.e.l.ls of this genus, that the species can only be fixed by ample descriptions and very correct figures. The figure is from a sh.e.l.l in the Linnaean Society's cabinet. Mr. Say says it is common in the Delaware River, North America.

Pl. 58

[Ill.u.s.tration]

ACHATINA crenata.

_Green hair-streaked Achatina._

GENERIC CHARACTER.--See Pl. 30.

SPECIFIC CHARACTER.

_A. (Div. 2.) testa alba, fasciis viridibus capillaribus; spira elongata, subattenuata, anfractibus 6 convexis, labio exteriore crenato; basi subtruncata._

Sh.e.l.l white, with capillary green bands; spire elongated, sub-attenuated, of six convex volutions; outer lip crenated; base slightly truncate.

A few specimens of this most delicate and beautiful sh.e.l.l were found by my brother, Mr. J. T. Swainson, jun. in the island of Cuba; nor am I aware of its having by any other means reached our cabinets, excepting a distinct variety which occurred in Mrs. Angus's, and is now (together with a young one of the same) in Mr. Dubois's collection. This has, in addition to the green bands on the spire, a row of bead-like cinereous spots at the base of the first and second spiral whorl; and others of a longitudinal square form on those whorls nearest the tip, which, with the inner lip, is slightly tinged with pink. The form of the sh.e.l.l also is shorter; but the general contour, and particularly the crenated mouth, common to both, clearly proves it can be considered only as a distinct variety. The specimen we have figured agrees with all those sent at the same time, in having not the slightest appearance of spots, though in a perfect state of preservation.

The little notches on the margin of the lip are always placed at the commencement of each of the green lines; the base of the column is straight, and slightly truncated before it joins the outer lip.

Pl. 59

[Ill.u.s.tration]

PSITTACUS Barrabandii.

_Red-collared Parakeet._

GENERIC CHARACTER.--See Pl. 1.

SPECIFIC CHARACTER.

_P. viridis, sincipite gulaque flavis; torque coccineo circa medium cervicem extendente; rostro rubro; alis spuriis caerulescentibus._

Green, fore-part of the head and throat yellow; round the middle of the neck in front an orange-red collar; bill red; spurious wings blueish.

The vast and little known region of New Holland has afforded us some of the most beautiful birds of this superb family, and among which the species now, as we believe, for the first time published, will stand conspicuous.

It is from a fine skin in the possession of Mr. Leadbeater, and is named in honour of the late M. Barraband, the first ornithological painter that France or any other country has produced.