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XXV. Researches on Foraminifera. — Fourth and concluding Series. 
By William B. Carpentee, if.D., FR.S., F.G.S,, F.L.S. 
Received June 14, — Read June 14, 1860. 
172. I HAVE now to bring to a close my account of the structure of those typical forms 
of Foraminifera which it has been my object to elucidate, by a description of four 
remarkable generic types ; of which the first, Potystomella, has long been known, but 
has been hitherto very imperfectly comprehended; the second, Calcarina., has never 
been carefully studied ; the third, Tinoporus., has only been very imperfectly known in 
one of its forms ; and the fourth, Carpenteria., is altogether new. Each of these will be 
found to present features of interest peculiarly its own ; — Polystomella being remarkable 
for the very symmetrical distribution of its canal-system, whose existence and whose 
relation to the multiple fossae upon its surface have hitherto been altogether overlooked ; 
— Calcarina being distinguished by the extraordinary development of its “ intermediate” 
or rather “ supplemental skeleton,” and by the amplification of the canal-system for its 
nutrition ; — Tinoporus presenting us with a type of structure that is intermediate between 
the Eotaline group (to which it is allied in the character of its individual chambers) and 
the Orhitoline (to which it approximates in its mode of growth), and that helps us 
greatly in the interpretation of the structure of the fossil Orhitoides-, — and, lastly, 
Carpenteria furnishing us with a connecting link of the most striking significance between 
Foraminifera and Sponges. 
Genus Polystomella. 
173. History. — Of the minute shells to which the generic name Polystomella is now 
assigned, one species, now known as P. crispa, seems to have early attracted the atten- 
tion of conchological observers and collectors, on account both of its beauty and of the 
frequency of its occurrence ; having been described and figured more than a century ago 
by Plancus and Gualtieri, and adopted by LixisrAEUS under the designation Nautilus 
into his ‘ Systema Naturae.’ By this designation it continued to be known from the 
time of Lmx^us to that of Lamarck ; having been described and figured by Walker, 
SoLDAXi, Ficiitel and Moll, Montague, Dillwyx, and many other writers of the latter- 
part of the last and the early part of the present century. Its dissimilarity to Nautilus 
was first clearly pointed out in 1822 by Lamarck; who conferred upon it the generic 
distinction Polystomella^ apparently under the impression that the numerous pits on its 
surface are really multiple mouths of passages leading directly to its chambered cavity. 
His definition of the genus, contained in the First Edition of his ‘ Animaux sans Ver- 
tebres ’ (tom. vii. p. 625), is as follows : — “ Coquille discoide, multiloculaire, a tours 
