Nomenclature of the Forarninifera. 315 



CristeUaria Crepidula runs insensibly into C. Cassis on one 

 hand, and on the other into the Planularian section of the Va- 

 ginulirwe. It is common wherever Cristellaria are abundant, 

 whether in the fossil or recent state. The specimen figured by 

 Soldani (Testaceogr. vol. i. p. 64, pi. 58. fig. b b) is very similar, 

 to N. Crepidula, as Fichtel and Moll supposed. 



22. Nautilus Cassis. Page 95. Five varieties. " Fossil : 

 Coroncina." 



a. PL 17. figs. a-d. Plancus, Conch, p. 120, pi. 1. fig. 11 Q R. 

 13. PL 17. figs. e-ff. Soldani, Oritt. p. 97, pi. 1. fig. 1 A B C. 



7. PL 17. figs. A, t- 



8. PL 17. figs. *, /. Soldani, Testaceogr. vol. i. p. 63, pi. 55. 



fig. A. 

 e. PL 18. figs. a-c. 



We have here some modifications of a varietal form of Cris- 

 tellaria, discoidal and foliaceous, apt to be ornamented by clear 

 granules at the centre and along the septal lines, and to expand 

 itself into a broad and serrate keel. 



Individuals of this variety are often pre-eminent among 

 CristeUaria for their size and elegance. Their sinuous and, as 

 it were, loosely-set chambers, their flatness, and the irregular 

 position of the aperture, remove them but a little way from the 

 typical C. Calcar. In the var. e the aperture is so nearly central 

 that the chambers grow saddle-shaped, and present us with the 

 essential characteristic of Flabellina. Hence the removal of 

 another supposed " generic " limit, nay, of a " specific " 

 boundary. 



Cristellaria of this shape and size occur in the Italian 

 Subapennine Tertiaries, and also at Malaga in Spain. Indivi- 

 duals of smaller growth abound in some Secondary and Tertiary 

 deposits, and also in recent seas. In the muds dredged off the 

 Abrolhos Bank, in about 30 fathoms water*, we have similar 

 Cristellaria, almost rivalling the Subapennine specimens. 



Besides the references to Soldani and Plancus above noted, 

 Fichtel and Moll refer with justice to Soldani (Testaceogr. vol. i. 

 p. 63, pi. 55. figs. A-G, and pi. 56. figs. H-N) for figures of 

 various forms of CristeUaria Cassis. 



23. Nautilus Galea. Page 100, pi. 18. figs. d-f. " Fossil : 

 Coroncina." This is a fine, outspread, extremely flattened, 

 smooth, and broad-keeled CristeUaria Cassis, with very widely 

 transverse chambers, the inner extremities of which stretch be- 

 yond the spire. In this feature we have an interesting isomor- 

 phism, if we may so term it, with other and not related generic 

 forms. This individual, with its attempt at cycloid growth, re- 

 minds us of the Peneroplis planatus, in its broadest forms, out- 

 * By Capt. Richards, H.M.S. < Plumper.' 



