. Cassell's natural history. Animals; Animal behavior. NATURAL Figs. 29-33.—FORAMINIFERAL SHELLS. (AtUr d'OrMjii!/.) J, Plannrbulina racditerranensis: 30, Pcneroplis (Dendritina) arliUBCula ; 31, Calranna defraricii; rginnta; 33. Uvigerina pygmra, figured with the aperture down- builcUngs have been constructed—^uch as the Cathech-al of Gerona and some of the Pyramids of Egypt. Fusidina (distaff) is a spindle-shaped Nummulitid forming masses of limestone of Carboniferous age in Russia and North America. This form, Alveoliiui, and Lofiusia, resembling one another in shape, belong to qu
. Cassell's natural history. Animals; Animal behavior. NATURAL Figs. 29-33.—FORAMINIFERAL SHELLS. (AtUr d'OrMjii!/.) J, Plannrbulina racditerranensis: 30, Pcneroplis (Dendritina) arliUBCula ; 31, Calranna defraricii; rginnta; 33. Uvigerina pygmra, figured with the aperture down- builcUngs have been constructed—^uch as the Cathech-al of Gerona and some of the Pyramids of Egypt. Fusidina (distaff) is a spindle-shaped Nummulitid forming masses of limestone of Carboniferous age in Russia and North America. This form, Alveoliiui, and Lofiusia, resembling one another in shape, belong to quite different groups; an example of the imperfection of d'Orbigny's. classification based on the shape of shell and setting on of the chambers. In many of the Foraminifera, especially the Porcellana, the chamber-walls merely tent over the sarcode, whether thread-like, beaded, folded, or spiral; the edges of the new chamber resting oii the surface either of the object to which the Forarainifer is. attached, or on a former whorl of the shell. In more highly- developed hyalhie species, each segment of sarcode becomes wholly coated with perforated shell-matter, except where it is attached by the stolon to the previous segment, and where it gives oft' a new bud. Further, the sarcode is thrown back over the already formed chambers more or less freely, and the test gets thickened, and sometimes ornamented with supple- mental shell-growtli. But a most important feature in the best kind of these shells {Nummulites, I'olystomella, Eotalia, Calcarina, &c.) consists of a system of vessels, or canals, formed between the consecutive chambers of such well-coated kinds, and continued in a spiral manner along the upper and lower edges of the chambers, and communicating either directly with the surface {Polystomella), or through a reticulation of similar vessels m the thickened edge or " marginal cord " of the shell. Tliese vascular portions have been termed the "intermedi
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