26 THE FORAMINIFERA 



arenaceous, and clearly a Trochauimina^ closely allied to T. squa- 

 mata. Parker and Jones figure a thick specimen in their "Forami- 

 nifera of the North Atlantic and Arctic Oceans," page 407, PL XV., 

 Figs. 30, 31. They note its resemblance to some of the Discor- 

 bi?ice, but do not appear to have identified it with Williamson's 

 species. 



Trochammina inflata is a brown, polished shell, with sub- 

 globose, inflated chambers, reminding one of Rotalia Beccarii. It 

 has a few deep-coloured, small initial chambers, visible on the 

 upper surface ; frequent. 



Trochammina macrescens, also brown, with a sunken, shri- 

 velled appearance of chambers ; very rare. 



Trochammina plicata. — Terquem,in his essay on the "Recent 

 Foraminifera of Dunkerque," second fascicule, page 72, PL 8, 

 Fig. 9, describes a form to which he gives the name of Patellina 

 plicata. We have found a few specimens which are apparently 

 identical with his species, but they are finely arenaceous, and must 

 be assigned to the genus Ti'ochamnmia. Terquem does not men- 

 tion that his examples are arenaceous, but it must be understood 

 that he attaches little importance to the material of which the 

 shells are composed. This variety of T. squamata differs from 

 T. ochracea in having fewer chambers in each whorl (six being the 

 number in each of the specimens discovered ; whilst T. ochracea 

 has nine or ten), and from the typical T. squamata is the tortuous 

 septal wall, and the subdivision of the chambers. 



HYALINE FOKMS. 



LAGENiE are the simplest hyaline, unilocular shells, having an 

 external or internal tube. When the neck is produced into an 

 external tube, it is said to be " ectosolenian " ; when, by invagina- 

 tion, the tube is internal, it is called " entosolenian." The young 

 shell is transparent, like glass, becoming frosted by age from the 

 accumulation of shell-matter, traversed by minute tubes, which 

 give an opacity to certain parts, or to the whole of the surface. 

 The shell does not increase in size, from which it may be inferred 

 that the animal is full grown before it begins to secrete the shelly 

 matter. 



Some authors are inclined to include the whole group as one 

 species, so many inosculating forms connect all the so-called 

 species. 



