. Bulletin - United States National Museum. Science. i^ UNITED STATES NATIONAL JVIXTSEUM BTJLLETm 215 Spherical: Individual chambers forming spheres as in Globigerina bulloides d'Orbigny. Clavate: Chambers elongated and may be inflated terminally, having a club-shaped appearance as in Clavigerinella akersi BoUi, Loebhch, and Tappan. TxjBULOSPiNATE: Chambers produced radially into long hoUow extensions, or tubulospines, as in Schackoina. Radial elongate: Chambers produced radially as ia Rugoglobigerina hantkeninoides Bronnimann. Accessory Structures These include the structures previously known
. Bulletin - United States National Museum. Science. i^ UNITED STATES NATIONAL JVIXTSEUM BTJLLETm 215 Spherical: Individual chambers forming spheres as in Globigerina bulloides d'Orbigny. Clavate: Chambers elongated and may be inflated terminally, having a club-shaped appearance as in Clavigerinella akersi BoUi, Loebhch, and Tappan. TxjBULOSPiNATE: Chambers produced radially into long hoUow extensions, or tubulospines, as in Schackoina. Radial elongate: Chambers produced radially as ia Rugoglobigerina hantkeninoides Bronnimann. Accessory Structures These include the structures previously known vari- ously as secondary chambers, chamberlets, umbUical plates, etc., but which are not true chambers as they do not foUow the normal chamber arrangement. They are commonly related directly to the aperture and thus may be considered as apertural modifications (text-fig. 4). A prominent feature of these accessory structures is that they become progressively more prominent with growth of the test and some are developed only in the adult, so that dissection of the tests fails to show any trace of such features as the bullae of the Catapsydra- cinae. This has been noted before, as F. Parker (1954,. p. 477), in discussing a species found in the Gulf of Mexico, stated, "Globigerina sp. has a thin supplement- ary chamber extending from the dorsal side between the last-formed chamber and the first one in the last- formed whorl, to varying degrees over the umbihcus. There are supplementary apertures along the sides of this chamber which in many respects is similar to the supplementary chambers of Globigerinita. This cham- ber is apparently resorbed or destroyed when new regular chambers are added since there is no trace of a previous ; It is probable that these additional structures serve to protect and reduce the size of primary or secondary apertures. They may also be a weight-increasing development necessary in the adult test to maintain the specific gravity of the an
Size: 1367px × 1828px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
