CROUANIA. 



C 215 ] 



CRUSTACEA. 



that family. The spores are contained in 

 a peridium, which bursts by a regular or 

 irregular apical orifice. 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 

 perithecium. C. Vincetoxid is the perfect 

 form of Uredo Vincetoxici. 



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

 188. 



CROUA'NIA, J. Agardh. A genus of 

 Cryptonemiaceae (Florideous Algae). C. 

 atienuata 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 branchlets, somewhat beaded. 

 The favellidia are stated to occur near the 

 tips of the branchlets; the tetraspores (large) 

 are affixed to the bases of ihe latter. 



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

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

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

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

 thamniori). 



CRUCIB'ULUM, Tulasne. A genus of 

 Nidulariacei (Gasteromycetous Fungi). 



C. vulgare occurs frequently on ferns, de- 

 cayed sticks, &c., and is found in many 

 parts of the world. 



BIBL. Sachs, Sot. Zeit. xiii. 833: Tulasne, 

 Ann. 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. Amfr. Mer. 1839 j 

 Carpenter, Introd. For. 80. 



CRUME'NULA, Duj. A genus of In- 

 fusoria, of the family Thecamonadina. 



Char. Oval, depressed, with a resisting 

 obliquely striated or reticulated tegument, 

 from a notch in the fore part of which a 

 long flap:elliform filament issues ; a red eye- 

 spot. Movement slow. 



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

 length 1-510". Filament three times as long 

 as the body. 



Dujardin appends Prorocentrum, E., to 

 this genus. 



BIBL. Dujardin, In/us, p. 339. 



CRUOR'IA, Fries. A genus of Crypto- 

 nemiacese (Florideous Algae). C. pellita 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 the rest. The 

 tetraspores occur at the bases of the fila- 

 ments. 



BIBL. Harvey, Mar. Alg. pi. 20 C ; Phyc. 

 Brit. pi. 117. 



CRUSTA'CEA. A class of Animals, 

 belonging to the subkingdom Articulata. 



Char. Apterous ; no tracheae ; respira- 

 tion aquatic (branchial), or effected by the 

 skin : legs jointed. A dorsal vessel, ven- 

 tricle, or heart; integument composed partly 

 of chitine. 



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 antennae. 



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 maxillae ; 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 maxillae is sometimes situated a soft, 

 tongue-like, sometimes cleft appendage. 

 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 



