CKISINA.. 
161 
1. Crisina unipora, d’Orbigny, 1850. 
STXONTilT. 
Crisina un 
Idmonea 
pora, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 265. 
d’Orbigny, 1851. Bry. Cret. pi. 613, figs. 1-5. 
d’Orbigny, 1853. Bry. Cret. p. 737. 
Beissel, 1865. Bry. aachn. Kr. : Xat. Verb. boll, maatscb. 
Wet. ser. 2, vol. xxii. p. 74, pi. viii. figs. 97-101. 
Hamm, 1881. Bry. mastr. Ober-Sen. p. 31. 
Marsson, 18S7. Bry. Riig. : Pal. Abb. vol. iv. p. 29. 
Age tuf . Ciply : BuU. Soc. beige Geol. vol. i. 
Pergens, 1888. 
p. 2ti4. 
Pergens, 1890. 
Waters, 1884. 
Revision, p. 342. 
non Crista ,, Waters, 1884. Cycl. Austr. : Quart. Journ. Geol. Soc. vol. xl. 
p. 683, pi. XXX. fig. 1. 
Crisina elegans, d'Orbigny, 1851. Bry. Cret. pi. 613, figs. 6-10. 
Idmonea francorum, Pergens, 1890. Revision, p. 343, pi. xiii. fig. 6. 
,, ,, Vine, 1893. Compl. Rep.: Rep. Brit. Assoc. 1892, p. 308. 
? EeUpora gracilis, von Hagenow, 1846. In Geinitz, Grundr. Verst, p. 592, 
pi. xxiii. b, fig. 4. 
Diagnosis. 
Zoarium of delicate branches, which divide dichotomously at 
considerable intervals. The branches are subcylindiical in 
cross section. 
Zooecia long. Apertures are usually single and alternate ; but 
there is occasionally a second aperture beside the principal 
one. The peristomes are low. 
Dimensions. 
B.M. 
B.M. 
Fide Pergens. 
D. 3979. 
D. 963. 
Diameter of average branches 
Distance of apertures on one 
'3-*4 mm. 
•5 mm. 
.. 'b mm. 
side of branch 
variable 
. -8 „ . 
•8 „ 
Diameter of aperture 
•09 mm. 
. -I-'IS „ 
.. 1 „ 
Distribution. 
England : 
Upper Cbalk : Gravesend. 
Middle Chalk : Cbatbam. 
Foreign : 
Senonian — Maastricbtian : Fecamp, Seine - Inferieure ; Maastricht ; 
Ciply. 
Campanian : Riigen. 
Turonian : Yendome, Loir-et-Cber. 
M 
