382 REPORT— 1869. 



an entirely new light. The varieties of this genus described by M. Terquem 

 from specimens found in the Lias formation of the north-east of France, 

 comprised only a few outspread, discoidal, rotalian forms of finely arenaceous 

 texture and variable septation — a series, in point of fact, structurally allied 

 to Trochammina, but with some morjihological resemblance to Rotalia. 



The modifications, both in structui'e and mode of growth, exhibited in the 

 forms about to be described, place the type on a much extended basis ; and 

 it will be seen how large a number of the simpler Foraminifera have their 

 analogues in the varieties of this polymorphic genus. 



So far from being, as hitherto supposed, an essentially Liassic type, the 

 genus Involutina has its fullest and most characteristic development in the 

 Carboniferous period. 



Of abeady described species the followiug have been found in mineral 

 veins and the adjacent stratified rocks : — 



Involutina Liassica, Jones, sp. Involutina nodosa, Terquem. 



„ polymorpha, Terquem. „ aspera, Terquem (?). 



„ silicea, Terquem. 



In addition to these there are a large number of forms not before noticed, 

 of which brief descriptions are now presented. The definition of their cha- 

 racters must be regarded as provisional to some extent, and founded on Mr. 

 Moore's specimens. The elucidation of the type is as yet by no means com- 

 plete ; but, through the kindness of Mr. Young of Glasgow, Mr. Leipner, and 

 Mr. W. W. Stoddart of Bristol, materials for more extended observations have 

 been placed at the author's disposal, which will form the basis of a future 

 memoir. 



Genus Involtttina, Terquem. 



/. cylinclrica, n. sp. Test elongate, cyHndi'ical, arcuate, tapering ; septation 



imperfect. 

 I. incerta, n. sp. Test biconcave, helicoid, the terminal portion leaving the 



spire at an angle ; septation very obscure. 

 /. recta, n. sp. Test crozier- shaped ; earlier chambers arranged spirally, 



later ones in a single straight series ; chambers somewhat ventricose ; 



septa constricted and well defined. 

 /. hhata, n. sp. Test lenticular, rotalian, lower surface sometimes concave ; 



periphery rounded ; chambers ventricose ; septa constricted. 

 I. radiata, n. sp. Test nautiloid, lenticular ; periphery sharp, subcarinate ; 



chambers long, narrow, often curved ; septal hues not constricted, but 



in many eases marked by a radiate sutural limbation. 

 J. crassa, n. sp. Test rotahan, turgid, subglobose ; chambers numerous, 



ventricose ; terminal chamber especially large and inflated. 

 I. obliqua, n. sp. Test inequilateral, compressed, formed of long curved 



chambers, coiled irregularly on an oblique axis ; septation indefinite ; 



terminal chamber investing one-half of the shell. 

 /. suhrotunda, n. sp. Test subspherical, formed by the acervuline growth 



of minute chamberlets on a central disk. 



In addition to these, two other more obscure varieties have been met with, 

 requiring further investigation. One of these, provisionally named /. vermi- 

 formis, resembles /. cylindroides, but has a test of uneven diameter and 

 irregular twisted contour, suggesting an uncoiled spiral with rudimentary 

 septa. The other, /. macella, has a large complanate nautiloid test, the 

 chambers marked by depressions, the septation very indistinct. 



