292 Messrs. W. K. Parker and T. Rupert Jones on some 



Globigerina concinna, G. diplostoma, and G. triloba, Reuss, Vienna Trans, 

 i. p. 373. pi. 46. f. 8-11. 



This well-known and extremely common species, essentially a 

 deep-sea shell, and of a fine rose-colour when fresh {G. rubra, 

 D^Orb.), is extremely variable in size and shape, though easily 

 recognizable. It affords several species to authors. 



It is excessively abundant in the Chalk (G. cretacea, D'Orb.), 

 rarer in the Gault, and abundant in nearly all Tertiary beds of 

 deep-sea origin, especially muddy deposits. It is the common 

 form in the deep-sea dredgings of the North Atlantic (Sub- 

 marine Telegraph) ; and we have it from Crete (at 360 fathoms), 

 and from the coasts of North Britain. It appears to be rare in 

 dredgings from shallow water and in sponge-sands. 



16. Rosalina vesicularis, Lamarck, sp. PI. X. figs. 22-24; 

 PI. XI. figs. 13, 14. 



Ammonia, Soldani, Sagg. Orittos. p. 104. pi. 3. f. 25. 



Discorbites vesicularis, Lamarck, Annal. Museum, vol. v. p. 183, vol. viii. 



pi. 62. f. 7; Defrance, Diet. Sc. Nat. pi : f. 2. 

 Rotalia (Discorbis) Gervilii, D'Orb. Ann. Sc. Nat. vii. p. 274. no. 36 ; 



Modeles, no. 72. 



Shell hyaline and finely perforate, discoidal, plano-convex, 

 exhibiting its spire more on the raised than on the flat surface ; 

 chambers overlapping to the umbilicus on the latter surface; on 

 the former, the chambers of the last whorl extending only half- 

 way over the earlier whorl; chambers curved on side-view; 

 varying from triangular to subquadrate, on one surface, with the 

 later ones lobular; on the other, long subtriaugular, with an 

 angular bend in the middle ; 16 apparent on the convex, and 

 1 1 on the flat surface. Aperture a slit at the base and terminal 

 edge of the chamber, combined with open slit-like spaces be- 

 tween the lengthened inner corners of the chambers on the flat 

 surface. These converging angles of the chambers are bordered, 

 along the posterior edge of each, with irregular growths of shell- 

 matter, varying from slight valvular laminae to coarse granular 

 accumulations ; in the latter case this overgrowth, extending 

 around and over the umbilicus, connects the umbilical processes 

 of the chambers and their little penthouse laminae into a rough- 

 ened mass perforated by irregular passages. 



One specimen of this fine large species of Rosalina with an 

 asterigerine umbilicus (fig. 24) was obtained in sand at West 

 Fiord (Nordland) from 60 fathoms depth ; and eight specimens 

 occurred on sponge from 100 fathoms at Vigten Island, Inner 

 Passage (Drontheim). 



Figs. 13 and 14, PI. XL, are young forms of this species, and 

 are not uncommon in the miscellaneous sand of the dredgings. 



