436 



ENTOMOSTOMATA EPACRIDE.E. 



blended together by Linnaeus in his genus Buccinum. 

 As each of these genera will be described in their 

 alphabetical order, a more detailed account will be 

 here needless. The general character of the genus, 

 as respects the animal, has already been given under 

 the article Buccinum. 



ENTOMOSTRACA (Muller). One of the two 

 principal sections into which the class of crustaceous 

 animals is divided by Muller, Latreille, and other 

 entomologists. By Linnaeus, the animals comprising 

 this division, and which are chiefly of small size, were 

 principally arranged in the genus Monoculus; but the 

 researches of various more recent authors, Schaffer, 

 Jurine, Ramdohr, Straus, Herman, and others, have 

 shown not only that these animals constitute various 

 different genera, but also orders and families. They 

 are aquatic animals for the most part, inhabiting fresh 

 water. Some of the species, however, including the 

 king crabs (Limulus, which is by far the largest species 

 in the section) are marine. Their legs, of which the 

 number varies, sometimes reaching more than a hun- 

 dred, are well adapted for swimming, being, indeed, 

 only employed for that purpose, for which end they 

 are either ramified or split, or else composed of flat- 

 tened joints. The branchiae, consisting of hairs or 

 setae, either isolated or united, forming pencils, are 

 attached to the legs, or to certain of them, or to the 

 upper or lower jaws. The shell covering the greater 

 portion of the body consists of one or two divisions, 

 and is very slender, being often mernbranaceous 

 and diaphanous. The integuments of the body are 

 rather corneous than crustaceous, in which respect they 

 approach the insects rather than the true Crustacea. 

 The mouth is very variable in its construction, con- 

 sisting either of jaws as in the Branchiopoda, or of a 

 sucker as the Pacihpoda, the majority of which latter 

 order are parasitic upon various species of aquatic ani- 

 mals. The young of the Daphniae and some other allied 

 genera, at their exclusion from the egg. scarcely differ, 

 except in size, from their parents ; whereas the Cyclops, 

 the PhyllopodcE, and Argulus, undergo decided trans- 

 formations, both in the form of the body and the num- 

 ber of locomotive organs ; indeed, in the latter organs 

 the uses as well as the number are altered in the pas- 

 sage to the adult state. The antennae of the Ento- 

 mostraca, of which the form and number are very 

 variable, are occasionally employed in locomotion. 

 The organs of generation are situated at the base of 

 the articulated abdomen or tail, which is never, how- 

 ever, terminated in an apparatus for swimming, nor fur- 

 nished with appendages in its lower surface, as in the 

 crabs and other Malacostraca, The eggs are either 

 carried within the shell upon the back, or are external 

 and borne beneath a common envelope in one or two 

 masses at the base of the tail. In some species the 

 eggs are capable of sustaining a long continued de- 

 siccation without losing their vitality. It is not until 

 after the third moulting that they become adult and 

 capable of reproduction. In a few instances it has 

 been observed, that, as in the Aphides, a single impreg- 

 nation is sufficient for several successive generations. 

 1 This section is divided into two orders, Branchio- 

 poda and PcBcilopoda, which see, as well as the 

 divisions there referred to, and also the general article 

 CRUSTACEA. 



EOLIDA, or EOLIS (Lamarck). A molluscous 

 animal, without any testaceous protection. The body 

 of the animal is oval, oblong, like that of a snail, 

 gasteropod ; the head very distinct, with two or four 



superior tentacula, besides two labial ; the branchia 

 are formed of a great number of small soft flexible 

 scales, imbricated on each side of the back. The 

 colts is one genera of the first family Trctracerata, 

 second order Polybranchiata, second class Parace- 

 phalophora, 



EPACRIDE^E, a natural order of dicotyledo- 

 nous plants, containing between twenty and thirty 

 genera, and upwards of one hundred and twenty 

 species. It is closely allied to EricecE, or the heath 

 tribe, and differs from it only in its anthers being one- 

 celled, and not furnished with appendages. 



The essential characters of the order are : calyx 

 five, rarely four-parted, often coloured and persistent ; 

 corolla hypogynous, monopetalous, the tube some- 

 times five-parted, the limb five, rarely four-cleft, some- 

 times bursting transversel}', in consequence of the 

 cohesion of the segments, deciduous or withering ; its 

 aestivation valvate or imbricated ; stamens generally 

 equal in number to the segments of the corolla, and 

 alternate with them ; filaments inserted on the petals 

 or hypogynous ; anthers simple, with a single recep- 

 tacle of pollen ; ovary sessile, usually surrounded at 

 the base with five distinct or connate scales, and 

 generally many-celled ; ovules solitary or indefinite ; 

 one style ; stigma simple, or sometimes toothed ; 

 fruit either a drupe, a berry, or a capsule ; seeds with 

 albumen. 



The plants belonging to this order are shrubs or 

 small trees, which are often covered with simple hairs. 

 Their leaves are alternate, rarely opposite, entire, or 

 serrated, often stalked ; their bases sometimes dilated, 

 overlapping each other, and half-sheathing the st em. 

 Their flowers are white or purple, sometimes blue, and 

 grow in spikes or terminal racemes, or are rarely 

 solitary and axillary. 



They are all natives of New Holland and the 

 islands of Polynesia, forming a striking feature in the 

 vegetation of those parts of the globe. They may 

 be said .to occupy in Australia the place which the 

 heaths do at the Cape of Good Hope. Many of the 

 species are remarkable for the beauty of their flowers, 

 and are on that account prized in greenhouses. 

 Some of them yield edible fruits, but in general 

 their properties are not known. 



The order has been divided into two sections : 

 1. The true Epacndece, including the genera Epacris, 

 Sprengelia, &c., in which the cells of the ovary are 

 many-seeded, and the pericarp capsular. 2. Styphe- 

 lice, comprehending the genera Slyphelia, Lissanthe, 

 Leucopogon, &c., in which the cells of the ovary 

 are one-seeded, and the pericarp indehiscent, rarely 

 capsular. 



The fruit of Leucopogon Richci supplied food to 

 the naturalist Riche when he was nearly perishing 

 from hunger in Southern Australia. The fruit of 

 Lissanthe sapida is one of the few edible fruits of 

 New Holland. It is of a red colour, and is as large 

 as a black currant, having something of the consist- 

 ence and taste of the Siberian crab. It is sometimes 

 called the Australian cranberry. 



EPEIRA ( Walckenaer). A genus of spiders, 

 comprising the largest and best-known British species, 

 Epcira diadema, a handsomely marked species, ob- 

 served in autumn suspended in its web in our gardens. 

 We are induced therefore in this place to make a few 

 general observations upon the order of which the 

 spider is the type, and which were accidentally omitted 

 in our alphabetical arrangement. 



