Miscellaneous. 423 
species. These groups, with their included species, were as 
follows :— i 
Group OvaTz. 
OvaT& La&vieat® :—Nucula ovata, Mant., Gault; WV. obtusa, 
Sow., Blackdown; WV. planata, Desh., Neocomian ; NV. cap- 
seformis, Mich., Gault. 
Ovarm ReEricuLATH: N. Metjert, sp. n., Blackdown; NV. arduen- 
nensis, Orb., pumila, var. noy., Gault. 
Group [upress®. 
NV. albensis, Orb., Gault; WV. impressa, Sow., Blackdown; J. 
Cornueliana, Orb., Neocomian; NV. simplex, Desh., Neo- 
comian. 
Group ANGULATZ. 
ANGULATH PECTINATA :—NV, pectinata, Sow., Gault; N. pectinata 
crete, sp. n., Grey Chalk; N. bivirgata, Sow., Gault; LN. 
antiquata, Sow., Blackdown. 
ANGULATA L&VIGATH :—V. gaultina, sp. n. 
Of the genus Leda no formal grouping was proposed; ten 
British Cretaceous species were described. In conclusion, the ~ 
author discussed the stratigraphical distribution of the species 
of the two genera. 
Dr. Gwyn Jurrreys doubted the necessity of forming a separate 
family of Nuculide. He included them in the Arcide. He had 
examined the Gault collection of Mr. Gardner, which appeared to 
contain ten times as many species as had already been described 
from that formation. He considered that the Gault Nuculide 
lived at a depth of from 50 to 100 fathoms, and this view was 
confirmed by the nature of the materials forming the Gault clay. 
Prof. T. Rupert Jonss said that in many parts the Gault swarms 
with Microzoa, and these seemed to confirm Dr. Gwyn Jeffreys’s 
view that the Gault was formed at a depth of about 100 fathoms. 
The Avrnor thought that the limited area covered by the true Gault 
clays and the presence of coniferous wood and fruits pointed to the 
conclusion that the Gault was an estuarine deposit. He believed 
the evidence indicated that the Gault was deposited in a gradually 
deepening sea. 
MISCELLANEOUS. 
Ou the Internal Sacculina, « new Stage in the Development of 
Sacculina Carcini. By M. Yves Drtace. 
Wen, in studyimg the embryogeny of Sacculina, one seeks on 
erabs for smaller and smaller individuals, one is soon struck by the 
