460 



at 



stance of what may be termed an Arboreal 

 Slug. It is a limaciform animal, which is 

 found crawling among the foliage of the 

 trees in the woods, and appearing more par- 

 ticularly after heavy showers. During the 

 heat of the day it collapses its broad, flat- 

 tened body, and retires under the shade of 

 large leaves, where it remains apparently in 

 a half torpid condition. It leaves no shiny 

 trail behind, when it crawls, as the limax 

 and snail do. It is of a chestnut brown 

 colour, minutely tuberculated, with nume- 

 rous small, dark, scattered spots, and with 

 the raised middle line of n pale brown ; the 

 eyes are terminal on the long superior pair 

 of tentacles." 



ONTSCIA. A genus of Mollusca, littoral 

 in its habits, and occupying an oblong, sub- 

 ovate, and slightly turbinated shell ; spire 

 short, base rather pointed ; aperture elon- 

 gated, terminating anteriorly in a short, 

 scarcely recurved canal ; outer lip thickened, 

 denticulated within ; inner lip expanded and 

 granulated : outside ribbed. 



ONISCID^E. There are several species of 

 Crustacea, of the order Isopoda, thus desig- 

 nated, some of which are terrestrial, and some 

 aquatic. The type of the group, Lygla 

 oceanica, is about an inch long, of a gray 



colour, with two large yellow patches on the 

 back. It is very common on the coast, 

 clinging to the rocks and to the parapets of 

 maritime erections. When it is attempted 

 to be seized it immediately folds up its legs, 

 and drops The terrestrial Onisciis fre- 

 quents dark and concealed places, such as 

 cellars, caves, holes in walls, under stones, 

 &c. They feed upon decaying vegetables 

 and animal matter, and only come forth 

 from their retreat in wet and moist weather. 

 They are popularly known by the name of 

 Wood-lice and Slaters. 



ONTIIOPHAGTJS. A genus of Lamelli- 

 corn Beetles living amongst dung. There 

 arc very many species. 



ONYCHORHYNCUS, or KING TODY. 



[See TODY.] 



OP AH, or KING-FISH. (Lampri* luna.} 

 This large and beautiful fish, though a na- 

 tive of the Eastern seas, has sometimes, 

 though very rarely, been met with on our 

 own coasts. It is about four feet and a half 

 in length, and weighs from 140 to 150 Ibs. : 

 the body is of an oval form ; the mouth 

 small, without teeth ; tongue thick, with 

 rough papillae pointing backwards. The 

 dorsal, pectoral, and ventral fins very long, 

 and falciform ; and the shape of the tail 

 lunate. The colours of the Opah are par- 



tic.ularly rich and showy ; the back and 

 sides are green, reflecting both purple and 

 gold in different lights, and passing into 

 yellowish green below. Above and beneath 



OPAH, OR KINO-FISH. (LAMPRIS LUNA.) 



the lateral line are numerous round, yel- 

 lowish-white spots ; and all the fins are 

 bright vermillion. This fish is held sacred 

 by the Japanese, who regard it as the pecu- 

 liar emblem of happiness. 



OPEN-BILL,. (Anastomus.} A genus of 

 Wading Birds, allied to the Storks and Ja- 

 birus. The mandibles of their beak come in 

 contact only at the base and tips, leaving a 

 wide interval between their edges, at the 

 medial portion ; the fibres of the horny sub- 

 stance of the bill in this part appearing as if 

 worn away. One species (Anastonttis osci- 

 tans) is whitish, with black tail-feathers : 



-BILL. 



another (4.1amclli(/er} is of a shining black, 

 and remarkable for the stem of each of its 

 feathers terminating in a narrow horny disc, 

 which passes beyond the vane. They are 

 natives of India. 



OPIIISAURUS. A snake met with in the 

 Southern United States ; about eighteen 

 inches in length, and of a yellowish green 

 colour, with black spots on the upper part : 

 the head is very small, and the tail is longer 

 than the body. So great is its fragility, 

 that, according to Catesby, a small blow with 

 a stick will cause the body to separate, not 



