CYRTOSTOMUM. 



[ 231 ] 



CYSTOPHRYS. 



inferior antennae ; labium or lower lip elon- 

 gated and triangular. Mandibles (fig. 20) 

 large, pointed at one end, with five teeth 

 at the other, and furnished with a three- 

 jointed setigerous palp, the basal joint of 

 which has a small branchial joint with five 

 terminal digitations. First pair of jaws 

 (fig. 21) consisting of a large basal plate (), 

 with four finger-like processes at its ante- 

 rior extremity, one of which is two-jointed, 

 and all terminated by several long fila- 

 ments : from the outer edge of this plate 

 arises a large elongated branchial lamina 

 (6) giving off from its crescentic margin 

 nineteen long pectinate spines. Second 

 pair of jaws (fig. 22) small, and composed 

 of two flattened joints, the terminal one 

 having several rigid hairs at the end, and a 

 lateral palp-like process. First pair of feet 

 (fig. 23) slender and five-jointed, the last 

 joint with a strong hook. Second pair of 

 feet (fig. 24) four-jointed, the last joint 

 terminated by two short hooks and a spur- 

 like posterior filament. 



Twenty-seven living British species. 



C. wrens (tristriata, Bd.) (PI. 20. fiors. 

 17-25). Shell oval, and somewhat reni- 

 form, posteriorly exhibiting three narrow 

 oblique streaks or dark bands ; valves con- 

 vex, green, and covered with dense short 

 hairs. Near the centre of each valve are 

 about seven small lucid spots. Fr. wat. 

 very common. 



Several fossil Ostracoda are referred to 

 Cypris by palaeontologists. 



BIBL. Baird, Entom. 151 ; Straus, Mem. 

 d. Mus. d. Hist. Nat. vii. 1821 ; Edwards, 

 Hist. N. Cntst. iii.; Brady, Linn. Tr. 

 xxvi. 360, and Ann. N. H. 1872, ix. 64 ; 

 Hup. Jones, Mon. Tert. Entom., Palceont. 

 Soc. 1836; Geol. Mag. vii. 158. 



CYRTOS'TOMUM, Stein. A genus of 

 Holotrichous Infusoria. 



C. leucas=Bursaria (Frontonia) I. 



CYSTIC OXIDE or OYSTINE. A 

 very rare component or constituent of uri- 

 nary calculi in man and the dog. It is 

 stated also to occur in the urine, in solution 

 and as a crystalline deposit ; but we have 

 never met with it. 



Cystine is insoluble in water and alcohol ; 

 soluble in mineral acids, but not in acetic 

 acid; also soluble in solutions of fixed 

 alkalies, their carbonates, and in solution of 

 ammonia. It is precipitated from its solu- 

 tion by acetic acid. 



Its crystals form colourless, regular six- 

 sided plates or prisms (PL 13. group 5) ; the 



larger crystals usually exhibit a number of 

 smaller hexagonal tables irregularly arranged 

 upon them; sometimes rectangular plates 

 are met with. The crystals usually exhibit 

 but little colour with polarized light. Cys- 

 tine is most readily obtained in crystals 

 from a calculus by solution in ammonia and 

 spontaneous evaporation. 



Some of the forms of lithic acid prepared 

 artificially, resemble those of Cystine (P1.12. 

 group 8 b] ; they may be distinguished by 

 the addition of ammonia, which dissolves 

 the cystine, but has little or no action upon 

 the uric acid. 



Carbonate of potash also somewhat re- 

 sembles cystine in the form of its crystals 

 (PI. 10. fig. 13) j but water or acetic acid 

 will at once distinguish them. 

 f CYSTICER'CUS,Rud. Formerly con- 

 sidered a genus of Cystic Entozoa; but 

 now known to be the scolices of Tcenia. 

 They consist of the short body of a Tcenia, 

 with the double crown of hooks and the 

 suckers, terminated posteriorly by a larger 

 or smaller cyst or vesicle. They occur in 

 the organs and the tissues of animals ; when 

 reaching the alimentary canal, becoming 

 developed into the perfect Teenies. They 

 have no sexual organs. 



C. cellulose (PL 21. fig. 3), the most 

 common, is the scolex of Tcenia solium. 

 The head is almost tetragonal, neck very 

 short ; body cylindrical, often longer than 

 the vesicle ; breadth of cyst half an inch ; 

 length of body, 1-6 to 2-5", or I" when ex- 

 tended. Occurs in the anterior chamber 

 and beneath the conjunctiva of the eye, 

 also in the voluntary muscles and brain of 

 man ; in the connective tissue of the pig, 

 producing " measly pork ;" also in the ape, 

 the dog, the ox, &c. C. tenuicollis of the 

 sheep is the scolex of T. marginata of the 

 dog; C. fasciolaris, of the rat and mouse 

 (PL 21. fig. 3 b, head) = T. crassicollis of the 

 cat; C. pisiformisofthe rabbit =T. serrata 

 of the dog ; C. talpce and C. longicollis, in- 

 festing moles, become respectively T. tenui- 

 collis and T. crassiceps of the fox. 



BIBL. Dujardin, Helm. 632; Monier, 

 Cysticerq. 1880 ; Beneden, Vers Cestoiden j 

 Cobbold, Parasites, and the Bibl. of TJENIA. 



CYS'TINE. See CYSTIC OXIDE. 



CYSTOCOC'CUS, Nag. = PBOTOCOC- 

 cus. 



CYS'TOPHRYS, Archer. A genus of 

 Rhizopoda 



2 species : C. Hackeliana and C. oculea, 



BIBL. Archer, Qu. Mic. Jn. 1869, 259. 



