14 



Crsatfttrg of Natural 



AMPHIPODA. An order of minute 

 Crustaceans, which have the power of swim- 

 ming and leaping with great facility, but 

 always on one side. Some are found in 

 streams and rivulets, but most in salt water ; 

 and their colour is of a uniform pale red or 

 greenish. In this order the eyes are sessile 

 and immoveable ; the mandibles are fur- 

 nished with a palp; the abdominal append- 

 ages are always apparent and elongated ; 

 and they have ciliae, 

 which appear to ful- 

 fil the office of bran- 

 chiae. The antennae, 

 ordinarily four in 

 number, are com- 

 posed of peduncle 

 and slender fila- 

 ment ; and the body 

 is mostly compressed 

 and bent. The ap- 

 pendages of the tail 

 '~" generally resemble 

 little pointed stylets. Among the Amphi- 

 pods most common on our shores are the 

 Sandhoppers, ( Talitrus locusta and Orchestia 

 littorea,) found under stones, or under the 

 mass of exuviae thrown up by the tide on 

 sandy shores, in troops of thousands, all ac- 

 tive and leaping when disturbed in their re- 

 treats. The following passage from Paley's 

 Natural Theology alludes to these minute 

 Crustacea : " Walking by the sea-side, in a 

 calm evening, upon a sandy shore, and with 

 an ebbing tide, I have frequently remarked 

 the appearance of a dark cloud, or rather 

 very thick mist, hanging over the edge of the 

 water, to the height perhaps of half a yard, 

 stretching along the coast as far as the eye 

 could reach, and always retiring with the 

 water. When this cloud came to be ex- 

 amined, it proved to be nothing else than so 

 much space filled with young shrimps in the 

 act of bounding into the air from the shal- 

 low margin of the water or the wet sand." 

 AMPHISB^NA. A genus of Serpents, 

 natives of South America, distinguished by 

 their bodies having nearly the same uniform 

 thickness throughout, by their small mouths 

 and eyes, short tails, and their numerous 

 rings of small square scales. The two best 

 known species are Amphisbcena alba and 

 Amphisbc&w fuliginosa. They are destitute 

 of fangs, and are consequently harmless and 

 inoffensive ; living, for the most part, upon 

 ants and other small insects. The colour of 



the first mentioned species is white, as its 

 name imports ; but in some specimens it is 

 tinged with pale rose colour, while in others 

 the head and back incline to a pale yellow 

 or brownish cast. The A. fidiginosa is 

 either black with white variegations, or 

 purple with yellow. The eyes of the Am- 



] phisbaena are covered, and almost concealed, 

 by a membrane; which, added to their natu- 

 I rally diminutive size, has given rise to the 

 popular opinion that the animal was desti- 

 tute of the organs of sight. The head is so 

 small, and the tail so thick and short, that 

 at first sight it is difficult to distinguish one 

 from the other ; and this circumstance, 

 united to the animal's habit of proceeding 

 either backwards or forwards as the occasion 

 may require, gave rise to the credulous belief 

 throughout the native regions of the Am- 

 phisbaana, that it has two heads, one at each 

 extremity, and that it is impossible to de- 

 stroy one by simple cutting, as the two heads 

 mutually seek one another, and soon re- 

 unite 1 



AMPHITRITE. A genus of Annelides, 

 belonging to the division Tubicolve, and easily 

 j distinguished by their large golden-coloured 

 i setae, disposed in a comb-like series or in a 

 i crown, or in one or several ranges on the 

 front of the head ; which may assist them m 

 locomotion, and probably serve them for 

 defence. Around the mouth are very nume- 

 rous tentacles, and on either side of the com- 

 mencement of the back are pectinated gills. 

 Some of them compose slight tubes, of a 

 regular conical form, which they carry about 

 with them, when running in search of food ; 

 these tubes, which consist of fine grains of 

 sand cemented together with great regularity, 

 are simple cones open at both ends, and not 

 attached ; they are usually about two inches 

 long, and may be frequently picked up on 

 our shores. [See TUBICOI^E.] 



AMPHIUMA. A genus of Batrachian 

 reptiles which abound in the lakes and stag- 

 nant waters of N. America. They first appear 

 in the tadpole form, respiring by means of 

 gills, and inhabiting the water ; they after- 

 wards gradually acquire small legs and feet, 

 and would have an appearance similar to 

 the water-newt, were it not for the extreme 

 length of their body. Though they are ca- 

 pable of existing on land, they seldom aban- 

 don the watery element. There are only 

 two known species, one characterised by 

 being three-toed, which is three feet long ; 

 the other, a much smaller species, having 

 only two toes. 



AMPULL ACER A. A genus of Mollusca, 

 allied to theAmpuUaria, two species of which 

 are found in great abundance in New Zea- 

 land, living in pools of brackish water, and 

 buried in sandy mud. When touched, the 

 animal enters very deeply into its shell, and 

 is at all times much hidden by it. The head 

 is large, flat, divided into two lobes, and 

 having two sessile eyes ; no appearance of 

 tentacula ; foot short and square. The shell 

 is thick and globular ; mouth round, or 

 oblique, having the lips united ; spire short ; 

 operculum thin and horny. 



AMPTJLLARIA. A genus of Mollusca 

 found in the rivers of Africa, India, and 

 South America. The shell is generally large, 

 thin and globular ; spire very short ; whorls 

 rapidly enlarging ; the operculum thin and 

 horny, and rarely calcareous. The animal 

 has a large head furnished with four tenta- 



