CRUSTACEA. 



[ 174 ] 



CRYPTOGLENA. 



the substance of the integument, impregnated 

 with calcareous salts, and frequently fur- 

 nished with direct prolongations in the form 

 of tubercles, spinous apjiendages, or hairs. 

 See Shell. The innermost layer consists of 

 a delicate fibrous coat, corresponding to an 

 internal periosteum or true skin ; it plays an 

 important part in the moulting process (ec- 

 dysis) which the Crustacea undergo, proba- 

 bl}'^ 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-hke, 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 feet converted into 

 jaws, and comparable to the six legs of In- 

 sects; these are furnished externally with 

 palpi. Next follow five pairs of true thoracic 

 legs, behind which are five pairs of false or 

 abdominal legs. 



The voluntary muscles of the Crustacea are 

 transversely striated. 



The eyes are either simple : consisting of a 

 convex cornea, behind which is a rounded 

 refracting body or lens ; this lies in a cup- 

 shaped mass of pigment, perforated by the 

 optic nerves ; — compound without facets : 

 consisting of a smooth cornea, behind which 

 a number of closely-placed eyes are situated ; 

 sometimes a modification of this form occurs, 

 in the existence of a smooth outer and an 

 inner faceted cornea ; — or compound faceted : 

 as in the eyes of insects. The facets are 

 frequently four-sided, but sometimes six- 

 sided. In some of the eyes a conical vitreous 

 body is situated behind the lens. The eyes 

 are sometimes sessile, at others stalked. 



The alimentary canal is usually short and 

 nearly straight, sometimes cui*ved or coiled. 

 Its wall consists of three or four layers — the 

 outermost, more or less fibrous, representing 

 a peritoneal coat ; the innermost, a transpa- 

 rent, structureless, epithelial coat, furnished 

 at the part corresponding to the stomach 

 with calcareous teeth, scales, or hairs, and 



which is thrown off during the ecdysis. Be- 

 tween these two coats is a layer of smooth 

 muscular fibres. 



The liver exists either in the form of sim- 

 ple follicles surrounding the alimentary ca- 

 nal ; of branched caeca situated at its upper 

 end, sometimes with short ducts ; or as two 

 glandular tufts or branches, consisting of 

 more or lessjamified and closely-connected 

 caeca, with short ducts. 



In many of the Crustacea the walls of the 

 alimentary canal are surrounded by cells 

 containing a bright orange-yellow or blue 

 fatty matter ; these are either scattered or 

 arranged in the form of lobules. They cor- 

 respond to the fatty body of Insects. 



The Crustacea undergo remarkable meta- 

 morphoses, the adult form frequently differ- 

 ing strikingly from that of the embryo. 



See AsELLus, Cirripedia, Entomo- 

 STRACA, Gammarus, Oniscus, and Si- 



PHONOSTOMA. 



BiBL. That of Animal Kingdom, and 



the Bibl. of the works there cited. 



CRYPTOCOCCEvE.— One of Kiitzing's 

 families of Algae, including his genera Cryp- 

 tococcus, Ulvina, and Sphcerotilus, all of 

 which appear to be forms of the mycelia 

 (com(ha?)of Mildew Fungi; they consist 

 of masses of extremely minute colourless 

 globules, found floating in aromatic waters, 

 vinegar, &c. 



CRYPTOCOCCUS, Kutz. See Cryp- 



TOCOCCEiE. 



CRYPTOGAMIA.— This term was ap- 

 ])lied by Linnaeus to his 24th Class, which 

 included all plants in which no true flowers 

 exist; the name signifying that the sexual 

 organs are hidden. In Natural Arrangements 

 of the Vegetable Kingdom the term is often 

 used in the same sense, but in this case as 

 one of two great divisions, being opposed 

 to Phanerogamia or Phaenogamia, which are 

 plants with the sexual organs conspicuous. 

 See Vegetable Kingdom. 



CRYPTOGLENA, Ehr.— A genus of In- 

 fusoria, of the family Cryptomonadina. 



Char. A red eye-spot ; carapace a scutel- 

 lum, rolled in at the margins, without a 

 neck. Aquatic. 



C conica (PI. 23. fig. 35 a). Conical, 

 expanded, and truncate in front, posteriorly 

 subacute; bluish-green; length 1-1160''. 

 Two flagelliform filaments. 



C. nic/ra (PI. 23. fig. 25 b). Ovato-sub- 

 globose, emarginate in front ; green ; length 

 1-1150". Motion slow; no cilia distin- 

 guished. 



