﻿CLIMACAMMINA. 



67 



inflated. Aperture simple. Texture finely arenaceous, nearly smooth. Length about 

 inch (04 3 mm.). 



The delicate little fossil, to which the specific name now adopted was some years ago 

 provisionally given, does not appear to have been otherwise figured or described. As a 

 species it is similar in many of its morphological characters to Haplophragmium Humboldti, 

 a Tertiary form described by Professor Reuss, 1 though it differs considerably in others. 

 For instance, H. Humboldti has a stoutly made test 3 mm., or about one ninth of an inch 

 in length, and with a much greater proportionate thickness than H. rectum, and is there- 

 fore many times the size of the slender Carboniferous form. Again, the spiral portion of 

 the shell of the Tertiary species, besides being relatively very large, has a sharp angular 

 periphery, whilst in the older form the helicoid chambers are of insignificant proportions 

 and have their margins rounded. Other differences might be enumerated, but in 

 the absence of intermediate varieties those which have been advanced are sufficient to 

 warrant distinctive appellation, though a larger supply of specimens would be necessary 

 to determine the range of variation to be included under the new name. 



Distribution. — Carboniferous Limestone (Yoredale) at Grassington, near Skipton, 

 Yorkshire, — very rare. 



Genus. — Climacammina, 2 Brady. 



Textularia, Brady (in part). 

 Clim &.CAMMINA, Brady. 



General characters. — Test free, consisting of many segments of irregular contour and 

 unevenly combined ; typically, biserial or subspiral in the earlier, uniserial in the later 

 stages of growth. Texture finely arenaceous. Interior more or less labyrinthic. Aperture 

 irregular or cribriform. Septation obscure. 



It has not been without considerable hesitation that the peculiar forms which were 

 at first referred provisionally to the genus Textularia under the name T. antiqua, 3 have 

 since been taken as the representatives of a generic group. That the specimens bear a 

 close analogy to the " Bigenerine " varieties of Textularia will be seen by reference to the 

 figures (PI. II, figs. 1 — 5), especially to those of the less irregular examples such as figs. 



1 Spirolina Humboldti, Reuss, 1851, ' Zeitschr. d. deutsch. geol. Gesel.,' vol. iii, p. 65, pi. iii, 

 figs. 17, 18. Subsequently as Haplophragmium Humboldti, 1866, ' Denkschr. math.-natur. Cl. K. Akad. 

 Wiss. Wien,' vol. xxv, p. 119, pi. i, figs. 1 — 4. 



2 Derivation, Greek ».A</ua£, KXtpaxos, a ladder, and afifios, sand. 



3 'Trans. Geol. Soc. Glasgow,' 1871, vol. iii, Suppl., p. 13. 



