COCCONEMA. 



[ 152 ] 



CODIUM. 



The upper valve differs from the adnate one 

 in not being furnished with the central no- 

 dule; under a low power it appears to have a 

 median line, as well as the adnate valve, but 

 this appearance, in some at least, arises from 

 the dots or markings at this part being more 

 closely in contact than elsewhere. 



C. pediculus (PL 12. fig. 17). Frustules 

 very slightly arched (front view) ; valves 

 elliptical, striae longitudinal, faint ; length 

 1-1200 to 1-700"; aquatic. 



C. placentula. Frustules flat; valves 

 elliptical; strise longitudinal, faint; length 

 1-760"; aquatic, common. 



C. scuteUum (PL 12. fig. 18). Frustules 

 dorsally convex; valves ovato-elliptical, strise 

 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; aquatic; length 1-900". 



C. Gremllii ~\ ,& -,1.x -/r 



mith * Marme> 



. 



Many other foreign species. 



BIBL. Ehrenb. Infus. ; Kiitzing, BacilL 

 and Sp Alg. p. 50; Smith, Brit. Diat. p. 21. 



COCCONEMA, Ehr. - A genus of Diato- 

 maceae. 



Char. .Frustules stipitate, navicular, 

 somewhat arched (side view) ; valves with a 

 submedian line, with central and terminal 

 nodules (= stipitate Cymbellai). Aquatic 

 (British). 



The valves are transversely striated, the 

 striae being resolvable into dots (depressions). 



C. lanceolatum (PL 12. figs. 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 

 dichotomous, jointed. 



C. cymbiforme. Scarcely distinct from 

 the last (Sm.); stipites 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 subra- 

 mose; length 1-450"; common. 



C. parvum (Sm.). Several other foreign 

 species. 



BIBL. Ehr. Infus. ; Smith, Brit. Diat.', 

 Kiitz. BacilL and Sp. Alg. 59. 



COCCUDINA, Duj. A genus of Infu- 

 soria, of the family Plaesconina. 



Char. Body oval, depressed or almost 

 discoid, often slightly sinuous at the margin; 

 convex, furrowed or granular and glabrous 



above ; concave beneath, and furnished with 

 vibratile cilia and cirrhi or corniculate 

 appendages, serving as feet ; no mouth. 



The species of this genus known to 

 Ehrenberg, are arranged among his Oxy- 

 trichina and Euplota. 



C. costata (PL 41. fig. 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 

 Ehrenberg's genus Aspidisca belongs here. 

 BIBL. Dujardin, Infus. p. 445. 

 COCK-CHAFFER. See MELOLONTHA. 

 COCK-ROACH. See BLATTA. 

 COCOA-NUT. The seed of the Cocoa-nut 

 Palm, Cocos nucifera (Monocotyledon). Sec- 

 tions of the remarkably hard shell of this nut 

 afford good specimens of very greatly consoli- 

 dated woody tissue, while the fleshy contents 

 form an example of oily albumen, the soft, 

 thick-w 7 alled cells containing abundance of 

 drops of oil in their cavities. The husk of the 

 nut is composed of fibres analogous in their 

 structure to liber, and used for similar 

 purposes. See FIBROUS STRUCTURES. 



CODIUM, Stackh . A genus of Siphona- 

 ce8e(CoiifervoidAlgse). Marine. The species 

 have dark green spongy fronds of cylindrical, 

 flat, globular or crust-like form, composed 

 of interlacing continuous filaments devoid of 

 septa, terminating in radiant club-shaped 

 filaments at the surface (fig. 133). The spo- 

 Fig. 133. 



Codium tomentosum. 



Saccate cells arising from the filaments at the surface. 

 Magnified 10 diameters. 



ranges (spores), are produced in lateral 

 branches from the clavate cells, forming 

 long elliptical sacs, the contents of which 

 are converted into a vast number of biciliated 

 zoospores, discharged when mature. 



BIBL. Harvey, Br. Mar. Alg. pi. 24 A; 

 Phyc. Brit. pi. 93. 35 B. ; and Thuret, Ann. 

 des Sc. nat. 3 ser. xiv. 232. pi. 23. figs. 1 5, 



