ON THE GENUS POLYMORPHINA. | 223 
Distribution.—The geographical range of P. oblonga seems to be limited; it is most 
abundant on the Devonshire and Cornwall coast, and may be found sparingly distributed 
at intervals all round the British Islands. We are not aware of its occurrence in the 
seas of warmer latitudes or in a fossil condition. 
POLYMORPHINA ANCEPS, Philippi. (Plate XXXIX. figs. 8, a-c.) 
Polymorphina anceps, Philippi, 1844, Beitráge zur Kenntniss d. Tertiürverstein. d. nordwest. Deutsch. 
pp. 41, 70, pl. 1. fig. 34. 
P. compressa, id. ibid. p. 69, pl. 1. fig. 35. 
Guttulina dilatata, Reuss, 1849, Denkschr. mathem.-natur. Cl. k. Akad. Wissensch. vol. i. p. 378, pl. 48. 
fig. 11. 
` Polymorphina dilatata, Reuss, 1851, Zeitschr. deutsch. geol. Gesell. vol. iii. p. 83, pl. 6. figs. 49, a, 5. 
? Strophoconus Hemprichii, Ehrenberg, 1854, Mikrogeologie, pl. 24. fig. 32. 
Polymorphina dilatata, Bornemann, 1855, Zeitschr. deutsch. geol. Gesell. vol. vii. p. 347. 
P. anceps, Reuss, 1855, Sitzungs. k. Akad. Wissensch. vol. xviii. p. 246, pl. 6. fig. 68, pl. 7. fig. 69 ; id. 
1864, ibid. vol. 1. p. 38, pl. 4. figs. 2, 3; id. 1866, Denkschr. math.-natur. Cl. Akad. Wiss. vol. xxv. 
p. 155, pl. 4. figs. 9-11. 
P; perneformis, Stache, 1865, Novara-Reise, vol i. 2** Abtheil. Paläont. von Neu-Seeland, p. 256, pl. 24. 
? P. cognata, id. ibid. p. 257, pl. 24. fig. 3. 
? P. contorta, id. ibid. p. 257, pl. 24. fig. 4. 
Characters.—Shell oblong, ovate, compressed, symmetrical, broad and rounded at the 
base, tapering towards the apex; periphery usually sharp-edged, sometimes slightly 
rounded. Chambers long, oblique, regular, springing from the base of the shell or near 
it. Septa marked externally by lines, or by slight depressions over the sutures. Surface 
smooth. Length +; inch. | 
The large biconvex or sometimes complanate Polymorphine, with broad, rounded 
base and oblique or nearly erect segments, constitute an assemblage which arrange 
themselves conveniently around the P. anceps of Philippi. As even the limited number 
of subdivisions which we have recognized for the purposes of nomenclature have no claim 
to be regarded in the light of true species, in the older acceptation of the word, the 
fact that such a series inosculates with kindred groups is of little consequence. It has 
therefore been thought preferable to retain both P. anceps and P. regularis as types of 
subdivisions, although they have recently been stated by Prof. Reuss to represent only 
extreme examples of the same species. 
Polymorphina dilatata, Reuss, represents an outspread variety with inflated chambers, 
rather than the regular biconvex form; and Ehrenberg's Strophoconus Hemprichii shows 
similar divergence from the type. Dr. Stache's three species (P. perneformis, P. cog- 
nata, and P. contorta) are intermediates that tend to establish the connexion alluded 
to between P. anceps and P. regularis. 
Distribution.—This is an essentially Tertiary Foraminifer; and, except Dr. Stache's 
.somewhat doubtful forms, which were derived from the New-Zealand beds, notices of its 
occurrence are almost entirely confined to the Tertiaries of Germany. 
