228 



should it be confounded with the genus Venus, since 

 it has not more than two teeth on each valve ; and 

 even appears to have but a very large one on the left 

 valve, the other projecting but slightly. The shell is 

 orbicular, transverse, equivalve, inequilateral, and 

 closed ; ligament external, and placed on the longest 

 side. Several species of this mollusk having been 

 described by authors previous to Lamarck, under the 

 name of Astarte, Sowerby very properly objects to 

 that of Crassina ; De Blainville has, however, included 

 it in that of Venus, and it stands in the second sec- 

 tion of the eighth family, Conchacea ; third order, 

 Lamellibranc/iiata ; third class, Acephalophora of his 

 system. 



* ASTATA (Latreille), DIMORPHA (Jurine). An 

 elegant genus of hymenopterous insects, belonging 

 to the section Fossores, or burrowing sand wasps, 

 and family Larnda;. The eyes are very large, 

 uniting behind in the males, whence the name given 



to these insects by Jurine ; the wings have one mar- 

 ginal appendiculated cell, and three submarginal 

 ones. These insects are extremely active, to which 

 the name astata has allusion, and they usually 

 provision their nests with the pupa3 of some of the 

 field bugs (Pentatonuz), the females in general 

 taking their stand upon small lumps of dry cow 

 dung, in hot situations. Mr. Curtis has figured a 

 species, under the name of Astata victor, but from 

 an examination of authentic continental specimens 

 of the Ast. abdominalis, it appears that his insect is 

 evidently that species. 



ASTELMA (R. Brown). A family of beautiful 

 undershrubs, natives of the Cape of Good Hope. 

 Linncean class and order, Syngenesia superflua ; na- 

 tural order, Composite. Generic character : antho- 

 dium imbricated, the inner scales channelled, and a 

 little coloured ; receptacle furrowed, downy ; florets 

 of the ray female, imperfectly attenuated ; pappus 

 hairy, rough, pencilled at the top, somewhat feathery. 

 There are ten species of this fine family, all of which 

 have formerly been known by other names, as gna- 

 phalium, elechrysum, &c. The genus is now arranged 

 in two sections, namely, Conniventia, involucres con- 

 nivent ; and Radiata, involucres radiate. 



ASTEPHANUS (R. Brown). A genus of two 

 species of climbing plants from the Cape of Gooc 

 Hope. Linnaean class and order, Pentandria Digynia 

 natural order, Asclcpiadeas. Generic character: co- 

 rolla somewhat bell-shaped, the throat of the tube 

 naked ; gynostegium like a bee. 



ASTER (Linnaeus) Starwort. An extensive fa- 

 mily of perennial plants, sixteen of which are shrubby 

 and the rest herbaceous. Linnaean class and order 

 Syngcnesia superflua ; natural order, Composite. Ge- 

 neric character : anthodium imbricated ; receptacl 

 naked ; radius of two colours. Of this genus there 

 are one hundred and fifty-four described. They are 

 found in many parts of the world, but chiefly in 

 North America. Almost all are ornamental, and de 

 corate our gardens in the autumnal months. Som 

 are splendid : one o'f them, A. amellus, was cele 

 brated by the Mantuan bard. The family is divide( 

 into eight sections, founded on the character of th 

 stem, number of flowers, and form of the leaves. 



ASTERIAS (Linnseus). A genus of shells be 

 .onging to the division Radiata (Cuvier), and t( 

 the class Echinodermata ; section, Stcllerides. 



This animal has a suborbicular depressed body ; it 

 circumference divided into angles, lobes, or rays 



ASTATA ASTERIAS. 



ach of which has a longitudinal furrow in its centre, 

 ringed on each side with moveable spines, and orifices 

 or the tubular or retractile feet; mouth central, and 

 ilaced beneath, at the union of the grooves, as in the 



Asterias rubens (Red Star-fish), with five lanceo- 

 ate, papillous, and spinous rays ; papillae of the back 

 scattered, and set nearly in rows. 



These animals inhabit the sea, and are usually found 

 on the sand, or among the rocks on the sea-shore, be- 

 ow high-water-mark. Their covering is a fleshy, some- 

 times coriaceous crust, defending them from the 

 attacks of smaller animals ; and they possess five or 

 more rays proceeding from a centre, in which their 

 mouth is situated. Each ray is furnished with a pro- 

 digious number of tentaculte, in some amounting to 

 fifteen hundred ; and when the animal is thrown on its 

 back, these may be observed projected and withdrawn, 

 like the tentaculae of snails ; by the undulatory mo- 

 tion of these rays the star-fish is enabled to swim, but 



its progression is extremely slow. Their powers of 

 reproduction are considerable ; for if by any violence 

 a ray be broken off, a new one will shortly be pro- 

 duced. The mouth is armed with bony teeth, which 

 are used in seizing and breaking the shells of fishes 

 on which the animal feeds ; from this a canal extends 

 to each of the rays, running through their whole 

 length, and becoming narrower as it approaches the 

 extremity. 



Persons wishing to preserve specimens of these 

 animals should kill them in brandy or other spirits, 

 keeping the rays expanded in their proper positions, 

 extracting afterwards the stomach and its contents 

 through the mouth by means of forceps. 



One species, the Asterias caput Medusa of Lin- 

 naeus (Medusa's head star-fish), mentioned by Shaw 

 in his Naturalist's Miscellany, is occasionally found 

 in most seas, but particularly at the Cape of Good 

 Hope. It has five equidistant thickly-jointed pro- 

 cesses proceeding from its centre, each of which is di- 

 vided into two other small ones, and each of these into 

 two other still smaller; and this mode of regular sub- 

 division is continued to a vast extent, and in the most 

 beautiful order of minute gradation, till at length the 

 number of ramifications amounts to several thousands. 

 One specimen, measuring three feet diameter, had 

 five hundred and twelve extremities to each ray, so 

 that the whole number amounted to two thousand rive 

 hundred and sixty. By this most curious structure 

 the animal becomes as it were a living net, and is ca- 

 pable of catching such prey as is destined by nature 

 for its support, the object being secured from all pos- 

 sibility of escape by the sudden contraction of these 

 innumerable ramifications. 



Marvellous stories are told of the size of these ani- 

 mals ; one traveller having asserted that they are 

 capable of entangling and drawing down a ship's 

 boat. This circumstance needs the confirmation of 

 other persons, though doubtless they sometimes attain 

 a very great size ; and it would appear that the 

 minute ramifications of the extremities of the radii 

 multiply in proportion to their distance from the 

 centre of the animal. The great difficulty of expand- 

 ing these animals in a dried) state without injuring 

 their delicate parts prevents their being frequently 

 measured. The state in which they are preserved in 

 cabinets presents the appearance of a turban, the 

 rolled edge of which is composed of countless ten- 

 taculae, intertwined in inextricable confusion, yet with 

 considerable symmetry of arrangement. 



