Ilydrnctinin, Parkcrin, and Strom atopora. 63 



kind lu'lp ot" my frit'iid ^Ir. Dallas, I iiave liecii pcrmiltc*! to 

 examine), wliosc graiuilatiMl siiriacc, close to the e<ljj;e ot" tlic 

 seel ion, wlierc it can be identilieil with the h(])iral lamina to 

 which it beloni^s, when viewed with the microscope, aided by 

 the addition of a little Avatcr covered by a thin glass disk for a 

 tem])orary varnish, presents the same reticulated structure with 

 (what were) the circular apertures, now filled with trans])arent 

 calesj)ar, varyini;" tVom 1- to 4-lS(KMhs inch in diameter. Tiiis, 

 in comparis(Mi with the diameter of the apertures of the radial 

 tubes (viz. 14-lHOOths inch) on the natural surface of a 

 Parkeria 1^ inch in thickness, seems very small; but then it 

 should be remembered that towards the centre of the Parkeria 

 this aperture is not more than O-lSOOths inch in diameter, 

 while in Ili/drnctinia calcnrca the aj)erture3 do not exceed 

 .'U-lSOOths inch, and in //. ccliinata the ccenosarcal stoloni- 

 ferous creeping tubulation is only 5-lSOOths inch in diameter, 

 &c. So that, after all, these apertures on the surface of 

 Lofiusiii were not relatively small. 



Com])aring the radial tubes in Loftusia with the single one 

 that unites the successively enclosing chambers of the ovoid 

 Foraminifera termed " ElUpsoidina^^^ as Mr. Brady has done 

 (j). 748), would lead one to infer that they finally opened on 

 the surface of Loftusia as in Parker m, which is just what 

 might be expected, although not actually stated by Mr. Brady. 

 Undoubtedly there is a great resemblance between the spiral 

 growth of Loftusia and that of the Foraminifera generally, 

 especially AlvcoUna) but here the resemblance ends; while a 

 " s])iral growth " is by no means peculiar to the Foraminifera. 

 Tiie general form also oi Lofusia is elliptical, as xwAlveoluw^ 

 but instead of the sigmoid longitudinal lines dividing the sur- 

 face of Alceolina into segments like those of an orange, with 

 transverse parallel lines between them, we have in Lofiusia a 

 minutely granulated surface, irregularly bossed, and sprinkled 

 with ])apilliform eminences about l-50th inch in diameter 

 (fig. 1<S, a, }>). At least this is what may be observed in the 

 large specimen of the Geological Society's Museum. 



And here it should be remembered that, in studying the 

 fossil structure, the white parts or lines represent the substance 

 of the test, and the dark ones the intervals Avhicli were 

 occupied by the sarcode ; at the same time, that a white line 

 may be merely the cylindrical wall of a dark interior, as seen 

 in the radial tubes of Parkeria under section. 



That Loftusia was irregularly bossed during growth may 

 also be seen in the section, which in this respect serves to con- 

 firm what, on the surface, might be doubted, from the quantity 

 of matrix left about the specimens, consisting almost entirely 



