Part 2: Researches on the Foraminifera

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                                of <u>Orbiculina</u>, however, being just as inaccurate as I have
shown those of <u>Obritolites</u> to be (partly, it seems likely, through his unacquaintance with the mode of making thin sections), there is no occasion to make further reference to them.

81. The excellent Memoir of Prof. Williamson <sup>1<sup> "On the 
minute structure of the Calcareous Shells of some recent species of Foraminifera", contains the first approach to a
correct description of the internat conformation of <u>Orbicu
lina</u>; and the fact was fully recognised by him, that in
advanced age, when the spiral type of growth has given place
to the cyclical, there is no other difference between the struc
ture of <u>Orbitolites</u> and that of <u>Orbiculina</u> than that which
arises from the dissimilarity of their earlier mode of de-
velopment. Although I am satisfied that, as to one or two
points of minute structure, Prof. Williamson has fallen
into error, I am disposed to attribute this to the want of a
sufficient number of well-preserved specimens for exam
ination; and for having it in my power to correct and ex
tend his description, I am chiefly indebted to Mr Hugh
Cuming, the specimens of this type included in his Philip
pine collection being remarkable both for their high develop
ment, and for their very beautiful state of preservation.

82. The investigations of Prof. Williamson are entirely
unnoticed by M. D'Orbigny in his latest classification of
the Foraminifera <sup>2<sup>; <u>Orbiculina</u> being ranked in the order <u>Helicostègues</u>, and being defined as follows, - "Coquille nauti
loide, comprimée, formée de loges divisées interieurement en
compartiments reguliers, percées de nombreuses ouvertures
_ _ _ _ _ _ 
1. Transactions of the Microscopical Society, 1st Series, Vol iii, p.120-
2. Cours Élémentaire de Palaeontologie, tom ii; Paris, 1852

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William Benjamin Carpenter
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Part 2: Researches on the Foraminifera, 1856. From The Royal Society, PT/53/8



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