198 Messrs. Parker and Jones on 



tessera, is an outspread, rhomboidal, Textilariform VirguJina 

 Hemprkhii. Fig. 19, Gr. rhomhoidah, = Bolivina dilatata. 

 Fig. 20, PUuritesy americ/xmis, Ls a sufjoblong Textilariform 

 Virgulina Hemprichii. Tig. 21, Strojjhoconus ajyicula?, is a 

 young Virg. Schreihersii, with a mode of growth approaching 

 that of Bvlimina elegantissirrui. 



Fig. 22, So^rina tongirostris, is " Loxostomum tuniens^'' the 

 smooth form of Heterostornella a/iuhata, not having grown gross 

 enough to produce exogenous shell-matter. Fig. 23, Proro- 

 ponis ohtijLSUs, is PolyniorpjJdna compjressa. Fig. 24, Pr. 6b- 

 tusv.a'i, is a Bigenerine Taxtxlaria, near to Bigenerina acaatJio- 

 ph/ra, pi. xxxi. figs. 30, 31,' and may pass as B. digitata. 

 Fig. 25, SpnroplerJxx americana (" Heterohelix, 1843, p. 429"), 

 is Tea?^ gihhosa with a spiral commencement, but without the 

 ornament of figs. 13 & 14 on the upper portion of this plate. 

 Fig. 26, Spiropjlecta rosula, is a straight-sided Textilaria of 

 the a/jglatinans t}^e, but commencing its growth with a large 

 coil of chambers. This species lives in the Atlantic, and in 

 its sandy condition has of late years been named by us Text, 

 hiformis^j and in the clear-shell state has received the name 

 of T. coraplexa from Mr. H. B. Bradyf; but Ehrenberg's 

 name has precedence. 



Fig. 27, Diraorphina saxipxxra, is an interesting specimen 

 of VirguUrm Schreihersii that has formed the latter part of its 

 shell in a uniserial manner, and has thus become Dimorphine ; 

 but the name '-'■ Dirof/rpldna''' is limited to the Dimorphous 

 forms of Polyraorpfdna. In Cassidulina, which is a very close 

 ally of Virgulina, we occasionally see evidences of weak and 

 rapid growth in one-sidedness and linear direction of the seg- 

 ments [Ehrenhergina). In accordance with tlie plan of no- 

 menclature among Foraminifera, the dimorphous varieties of 

 Bulimina\, Virgulina, Bolivina, and Cassidulina require one 

 or more subgeneric appellations. We propose Bifarina for the 

 dimoqjhous Virgulina ; and Bif. saxipara is the name with 

 which the interesting American specimen under notice will be 

 registered. 



Fig. 28, GuttuUna turrita, =Verneuilina pjygrnn;a (P^gger). 

 Fig. 29, Frondicul/xria'i strr/phoconus, is a small, smooth, 

 acute-ovate Glandulina loivigata, looking flat by reason of its 

 transparency. 



Fig. 30, Rotalia senaria, fig. 31, R. ghhulo8a-protolepta,SLT\di 



• Philos. Trans. 1862, vol. civ. p. 370, pi. 15. figs. 2-3, 24. 



t Nat, Hist. Trans. Northumberland and Durham, vol. i. part 1, I860, 

 pi. 12. fig. 0, p. 101. 



J livdimina variabilin, D'Orb., may be said to be dimorphous in this 

 8ens§, 



