Navicuhtcea.'] infusorial animalcules. 339 



CoscniTODiscus punciafifs. — Cells very small, radiating ; tweuty-lbiir 

 to twentj'-six in l-1200th ; loosely disposed at the centre, but dense 

 towards the margin, which presents a broad, ^'cllo-wish-whitc rim. 

 Diameter 1 -348th. Yiigiuia. 



C. clisciger. — Differs from C. perforatus by its ii-regnlarly circiilar, 

 not smooth, and larger umbilicus ; cells very small, dotted, and very 

 dense, indistinctly radiant; above thirty in l-1200th. Yii'ginia. 

 Diameter 1 -480th. 



C. (?) pohjstigma. — Differs from C. radiolatus by its much larger 

 radiant cells, fourteen in 1- 1200th ; rays converging, so as to form 

 two indistinct whorls (zones), perforated, and disposed side by side. 

 Diameter l-360th. If a species ofAtiliscus} (p. 321) In the North Sea. 



C. hetcro2)orus. — Cells hexangular, smaller at the margin, and ten 

 in 1 -1200th; intermediate ones five to six in l-1200th. Diameter 

 1 -360th. Bermuda. 



C. ompludantlm^. — Large, cells radiating, those of the margin 

 smaller, seven to eight in l-1200th, whilst at the middle there are 

 but six in l-1200th; centre occupied hj a rose-Hke stellate umbili- 

 cus, formed by seven to eight larger oblong cells. Diameter 1.96th. 

 Bermuda. 



C. Apollinis. — Surface covered w^ very dense pimctiform tubercles, 

 seventeen in 1-1 200th, of equal size, and in rows radiating towards 

 the margin. Diameter 1 -432nd. 



It differs from C. Lima, which it most nearly resembles, by the 

 greater number and denseness of its raj's, and by its larger size. 



C. (?) acthiochilus. — Centi-e of the disc occupied by punctate 

 tubercles, densely radiated with an umbilicus; margin (rim) wide; 

 irregularly dotted radiating lines (costte) of the margin, smooth, and 

 fifty-four in number. Diameter l-408th. Not unlikely constitutuig 

 a genus by itself. 



C. cingulatus. — Disc with pimctate tubercles, twenty-six in l-1200th; 

 dense, indistinctly radiant ; a small clear umbilicus ; margin with a 

 strong annular band, capable of being detached. Diameter 1 -552nd. 

 Stands between C. suUilis and C. gemmifer. 



C. (?) Gemmifer. — Disc with strong tubercles, loosely and elegantly 

 radiant, ten in l-1200th; a clear umbilicus. Diameter l-456th. 



