COCOONEMA. 



[ 188 ] 



COCOA. 



elliptical, striae longitudinal, faint j length 

 1-1200 to 1-700" j aquatic. 



C. placentula. Frustules flat j valves el- 

 liptical ; striae longitudinal, faint ; length 

 1-760" ; fresh water, common. 



C. scutellum (PL 16. fig. 18). Frustules 

 dorsally convex; valves ovato-elliptical, 

 striae transverse or slightly curved ; length 

 1-700" ; marine. /3. Nodule dilated into a 

 stauros. 



C. Thwaitesii (Achnanthidium flexellum, 

 Brebiss., Kiitz.). Ends of valves slightly 

 produced ; fresh water, length 1-900". 



C. Grevillii. Oval, with transverse cana- 

 liculi ; marine. 



C. diaphana. Elliptical, diaphanous; 

 marine. 



Rabenhorst describes 37 European spe- 

 cies, with numerous varieties; and enu- 

 merates 37 foreign species (with the re- 

 ferences). 



BIBL. Ehrenb. In/us. ; Kiitzing, BacilL, 

 and Sp. Alff. 50 ; Smith, Brit. Diat. i. 21 j 

 Rabenhorst, Flor. Alff. i. 98; GreviUe, 

 Micr. Tr. 1864, 9, 1865, 33, 1866, 126. 



COCCONE'MA, Ehr. A genus of Dia- 

 tom aceae. 



Char. Frustules stipitate, navicular, some- 

 what arched (side view) ; valves with a 

 submedian line, with central and terminal 

 nodules (= stipitate Cymbettce). Fresh 

 water. 



Valves transversely striated, the striae 

 being resolvable into dots. 



7 European species (Rab.). 



C. lanceolatum (PL 16. tigs. 19 & 20). 

 Front view of frustules lanceolate, truncate 

 at the ends ; valves semilanceolate, very 

 slightly inflated at the centre of the concave 

 margin; length 1-150". Common. Stipes 

 dichotornous, jointed. 



C. cymbiforme. Scarcely distinct from 

 the last (Sm.) j stipules filiform, obsolete, 

 interwoven into a gelatinous mass ; length 

 1-330". 



C. cistula. Front view elliptic-oblong, 

 obtuse ; valves inflated on concave margin ; 

 stipes elongate, filiform, simple or subrace- 

 mose ; length 1-450" ; common. 



C. parvum (Sm.). Several other foreign 

 species. 



BIBL. Ehr. Inf. ; Smith, Br. Diat. i. 75 ; 

 Kiitz. BacilL, and Sp. Ala. 59. 



COCCOSPH^E'RA, Perty. An obscure 

 genus of Infusoria (Algae ?), consisting of 



a black, 

 into ir- 

 diam. j 



they exhibit slow motion. In turf-pits 

 &c. 



BIBL. Perty, Kleinst. Lebens. 1852, 104. 



COCCOSPHERES. The name given 

 by Wallich to minute lumps of colourless 

 protoplasm, found in deep-sea ooze, and 

 floating in the tropics. He describes them 

 as spherical or multilobed, from 1-5000 to 

 1-830" in size, imitating in shape Orbulina, 

 Nodosaria, Textilaria, Rotalia, and Globi- 

 gerina, and coated with numerous oval 

 Coccoliths (PI. 23. tig. 56 a). 



From the Atlantic ooze, also, Huxley 

 describes minute granular colourless sarcodic 

 bodies as Coccospheres, 1-4500 to 1-1700" 

 in diameter, some having Coccoliths on or 

 in them ; and he distinguishes (1) the com- 

 pact, hollow, flattened sphaeroids with an 

 envelope, and (2) loose (1-4500 to 1-760"). 

 The corpuscles are free, touching or over- 

 lapping, 1-11000 to 1-4500" in breadth, 

 sometimesmingled with Coccoliths (1-1 1000 

 to 1-1600"). 



BIBL. That of COCCOLITHS, and Wallich, 

 Ann. N. H. 1877, xix. 342 (tigs.). 



COCCUDI'NA, Duj. A genus of Infu- 

 soria, of the family Plcesconina. 



Char. Body oval, depressed or almost 

 discoid, often slightly sinuous at the margin; 

 convex, furrowed or granular and glabimis 

 above ; concave beneath, and furnished with 

 vibratile cilia and cirri or corniculate ap- 

 pendages, serving as legs ; no mouth. 



The species of this genus known to 

 Ehrenberg are arranged among his Oxy- 

 trichina and Euplota. 



C. co&tata (PL 50. tig. 3). Body obliquely 

 narrowed and sinuous in front, convex and 

 furrowed above, or with from five to six 

 very projecting tubercular ribs ; appendages 

 grouped at the two ends ; the anterior more 

 slender and vibratile ; length 1-950" ; in 

 marsh-water. 



Three other species. Dujardin remarks 

 that EhrenbergV genus Aspidisca belongs 

 here. 



BIBL. Dujardin, Infus. 445; Claparede 

 and Lachmann, Infus. 188. 



COCKCHAFER. See MELOLONTHA. 



COCK-ROACH, or house black-beetle. 

 See BLATTA. 



COCOA. This substance consists of the 

 seeds of Theobroma Cacao (Ternstrcemia- 

 ceae), and is largely used in a manufactured 

 form under this name ; and, mixed with 

 sugar and other ingredients, it forms choco- 

 late. The various powders and pastes thus 

 designated are often very extensively 



