CROUANIA. 



[ 215 ] 



CRUSTACEA. 



tlint family. The spores are contained in 

 a peridiiim, which bur.sts by a regular or 

 irregular apical orific(\ The perfect spores 

 are produced on a columnar cellular body, 

 called the ligule, which rises out of the 

 centre of the Uredo-form or of its empty 

 peritheciuui. C. Vincetoxici is the perfect 

 form of Uredo Vincetoxici. 



BiBL. Tulasne, Ann. Sc, Nat. 4 ser. ii. 

 188. 



OROUA'NTA, J. Agardh.— A genus of 

 Cryptouemiaceae (Florideous Algaj). C. 

 atteniutfa is a very rare plant, which has 

 been found epiphytic on Cladostephus spon- 

 giosus. Its frond consists of a single-tubed 

 jointed filament, with the joints clothed 

 with dense whorls of minute dichotomously 

 multiplied brauchlets, somewhat beaded. 

 The favellidia are stated to occur near the 

 tips of the branchlets; the tetraspores (large) 

 are affixed to the bases of the latter. 



BiBL. Harvey, Mar. Alg. pi. 21 D ; Phyc. 

 Brit. pi. 106 ; J. Agardh, Akj. Medit. 83 ; 

 Agardh, Sp. Alg. ii. 136 (as Grijfithsia 

 nodulosa) ; Kiitzing, Sp. Alg. 651 (Calli- 

 thamnio7i). 



CRUCIB'ULUM, Tulasne.— A genus of 

 Nididariacei (Gasteromycetous Fungi). 



C. vtdgare occurs frequently on ferns, de- 

 cayed sticks, itc, and is found in many 

 parts of the Avorld. 



BiBL. Sachs, Bot. Zeit. xiii. 833; Tulasne, 

 Ami. Sc. N. 1844. 



CRUCILOCULI'NA, D"Orb.— A Trilo- 

 culine Miliola with a crucial fissure for its 

 aperture — that is, having four small symme- 

 trical valves, instead of one. Known only 

 from the Patagonian coast. 



BiBL. D'Orb. For. Amer. Mer. 1839; 

 Carpenter, Introd. For. 80. 



CRUME'NULA, Duj.— A genus of In- 

 fusoria, of the family Thecamonadiua. 



C7>ar. Oval, depressed, with a resisting 

 obliquely striated or reticulated tegument, 

 from a notch in the fore part of which a 

 long flagelliform filament issues ; a red eye- 

 spot. Movement slow. 



C. testa (PL 30. fig. 34). Green ; aquatic; 

 length 1-510". Filament three times as long 

 as the body. 



Dujardin appends Prorocentrwn, E., to 

 this genus. 



BiBL. Duiardin, Infus. p. 339. 

 CRUOR'iA, Fries.— A genus of Crypto- 

 nemiacese (Florideous Algae). C. 2)efHla is 

 common on exposed rocks and stones be- 

 tween tide-marks, forming a glossy purplish 

 skin, between gelatinous and leathery, upon 



smooth surfaces, in patches 2 to 3" in dia- 

 meter. This ' skin' is formed of vertical tufts 

 of simple articulated filaments imbedded 

 in a gelatinous matrix. One of the cells of 

 each filament is larger than tlie rest. The 

 tetraspores occur at the bases of the fila- 

 ments. 



BiBL. Harvey, Mar. Alg. pi. 20 C ; Bliyc. 

 Brit. pi. 117. 



CRUSTA'CEA.— A class of Animals, 

 belonging to the subkingdoni Articulata. 



Char. Apterous ; no trachea) ; respira- 

 tion aquatic (branchial), or effected by the 

 skin: legs jointed. A dorsal vessel, ven- 

 tricle, or heart; integument composed partly 

 of chitiue. 



The integument of the Crustacea usually 

 forms a hard calcareous shell, sometimes, 

 however, being leathery or horny ; it con- 

 stitutes an external skeleton. In its most 

 complex condition four layers are distin- 

 guishable : — an outermost, very thin, trans- 

 parent, and structureless or cellular — the 

 epidermis ; beneath this, a layer of pig- 

 ment-cells to which the colour is owing, but 

 sometimes the pigment is not contained 

 within cells ; under this is a thick layer, 

 forming the greater part of the substance of 

 the integument, impregnated with calca- 

 reous salts, and frequently furnished with 

 direct prolongations in the form of tubercles, 

 spinous appendages, or hairs. See Shell. 

 The innermost layer consists of a delicate 

 fibrous coat, corresponding to an internal 

 periosteum or true skin ; it plays an im- 

 portant part in the moulting process [ecdy- 

 sis) which the Crustacea undergo, probably 

 secreting the new layers of the integument. 

 The higher Crustacea (the Decapoda) 

 have mostly two pairs of antennfe. 



The oral organs consist of a transverse 

 labrum or upper lip ; beneath which is a pair 

 of powerful toothed mandibles, acting late- 

 rally, and furnished with palpi. Next come 

 two pairs of maxillpe ; the first are membra- 

 nous and hairy at the margin, but without 

 palpi ; the second are also membranous and 

 hairy, and correspond to the labium of In- 

 sects. Between the mandibles and the first 

 pair of maxillie is sometimes situated a soft, 

 tongue-like, sometimes cleft appendsge. 

 The oral organs undergo various modifica- 

 tions in the lower Crustacea ; these will be 

 considered under the respective heads. Be- 

 hind these are three pairs of secondary or 

 auxiliary jaws, or rather legs converted into 

 jaws, and comparable to the six legs of In- 

 sects ; these are furnished externally with 



