REPORT ON THE FORAMINIFERA. 
529 
This species, of which the earliest available description and figures are those given by 
Batsch in 1791, is the best representative of the costate varieties of Marginulina. 
Individual specimens vary a good deal in contour, and also as to the number and degree of 
development of the superficial ribs ; but the stout proportions of the shell, its sub- 
cylindrical form and comparatively slight curvature, the inflated character of the later 
chambers, and the marginal aperture, are generally sufficient to distinguish it from costate 
varieties of Vaginulina and Cristellaria. The test is often more or less compressed just 
at the commencement, and occasionally presents a sharp or even subcarinate edge at the 
aboral end, but more frequently the margin is rounded from the beginning. 
Starved, tliin-shelled specimens of Marginulina costata have been found from time to 
time in the British seas, though they are of rare occurrence. In its fully developed 
condition, the species has been obtained from various parts of the North Atlantic, at 
depths of from 370 fathoms to 1240 fathoms; from the South Atlantic at still greater 
depths ; from the Mediterranean, and from the Adriatic. Except a few small ill- 
characterised exanrples, taken at a depth of 150 fathoms off the coast of New Zealand, 
it has not been observed in either the North or South Pacific, the Southern Ocean, 
or the Bed Sea. 
Fossil specimens have been described, under a number of different names, from the 
Liassic marls of England, Ireland, and France ; the Kimmeridge Clay ; the Cretaceous 
formations of Ireland and Germany ; the Miocene beds of Austria ; the later Tertiaries 
of Italy and Spain, and the Crag of the Eastern Counties. 
Vaginulina, d’Orbigny. 
“Cornu Hammonis,” Plancus [1739]. 
Orthoc&ra, Orthoceras, seu Orthoceratium, pars, Gaultieri [1742], Soldani, Batsch, Lamarck, 
Defrance. 
Nautilus, pars, Linne [1767], Batsch, Walker, Montagu, Dillwyn. 
Planularia, Defrance [1824], Blainville, d’Orbigny, Cornuel, Parker and Jones, Brady, Blake, 
Walford. 
Vaginulina, d’Orbigny [1826], Roemer, Michelotti, Philippi, Reuss, Bornemann, Neugeboren, 
Costa, Parker and Jones, Giimbel, Karrer, Seguenza, &c. 
Citharina, d’Orbigny [1839], Reuss. 
Marginulina, pars, Reuss [1851], Terquem. 
Dantalina, pars, Williamson [1858], Parfitt. 
The quasi- generic term Vaginulina may be conveniently adopted for those compressed 
and complanate varieties of Nodosarince which have oblique segments and a marginal 
aperture. Such forms are generally somewhat curved or arcuate, and taken collectively 
they are almost equally related to the Dentaline Nodosarice, the Marginulince, and the 
ensiform modifications of Cristellaria. No sharp lines of demarcation can be drawn 
between these allied groups ; but in general terms it may be said that Vaginulina is 
distinguished from Marginulina by its more or less flattened contour, from the curved 
