114 Messrs. W. K. Parker and T. R. Jones on the 



deposits rich in Cristellarice) we have the link with the Margi- 

 nuline variety of Nodosaria Raphanus, especially in the Viennese 

 specimen^ which is narrow -chambered^ pinched, and umbilicate, 

 like the crozier-part of a Marginulina. This linking is not only 

 shown by the form, the aperture, and the general structure of 

 the shell, but markedly in the style of ornament. The orna- 

 mentation of ribs is highly characteristic of the Nodosarine 

 group. In Nodosarice the riblets are often fully and symmetri- 

 cally developed; in some Marginulina; the rib on the convex 

 border surpasses its fellows; in Cristellaria; it is often the only 

 remnant of these ribs ; but in some varieties, as in Rohulina 

 echinata, D'Orb., R. ornata, COrb., and especially in R. Arimi- 

 nensis and Fichtel's Nautilus costatus, the rib-ornament still 

 bears evidence of the relationship mutually borne by these 

 diversely modified forms. Hence one of the grounds for the 

 foundation of the comprehensive genus Nodosarina^, intended 

 by us to embrace the Nodosarice, Cristellaria, and all the inter- 

 mediate and associated varieties. Indeed, we see as yet no 

 essential characters in this protean group whereby more than 

 one real species can be established, although we have examined 

 thousands of forms, not to say individuals, from the Permian, 

 Triassic, Liassic, Oolitic, Cretaceous, and Tertiary deposits, as 

 well as from deep and shallow seas of all parts of the world, 



20. Nautdus acut-auricularis. Page 103, pi. 18. figs. g-i. 

 " Recent : zoophytic concretions, Mediterranean.'^ A sub- 

 globose or ovoid Cristellaria, with numerous smooth, narrow, 

 flush chambers, slightly keeled. This is a variety intermediate 

 between C. Calcar and Defrance's Saracenaria Italica. It is 

 also nearly related to C. arcuata, D'Orb. (For. Foss. Vien. pi. 3. 

 figs, 34-36). This ai)pcars to be a rather rare and small form. 

 Fichtel and Moll's reference to Soldani, Testaceogr. vol, i. p. Gl, 

 pi. 49. fig, X, for this form, is correct, 



21. Nautilus Crepidula. Page 107, pi. 19. ^^s.g-i. "Recent : 

 Leghorn coast." A delicate, elongate, Marginulinc, flattened 

 Cristellaria. This variety, which by nmumcrable Unkings passes 

 into C. Calcar, is so readily modified by external conditions as 

 perhaps not to be represented by any two perfectly similar indi- 

 viduals. D'Orbigny's C. cyinboides (For. Foss. Vien. pi. 3. figs, 

 30, 31) is almost an exact counterpart of Fichtel's figure; but 

 in the former the coil is more open, C. compressa, D'Orb, {loc. 

 cit. figs. 32, 33), and C. lanceolala, D'Orb. (/. c. figs. 41, 42), as 

 well as Montfort's "Astacole crepidule," which is Blainvillc's 

 and Defrancc's " Crepidulinc astacolc " (Diet. Sc. nat, ])1, 19, 

 fig. 8), are similar attenuate, but keeled, varieties of Cristellaria 

 Calcar. 



* Annals, 1859, lii. p. 4/7, 



