GLOBIGERINA 8 1 1 



of the Foramiiiifera into the arenaceous and calcareous groups does 

 not correspond to any natural arrangement ; for, although the rule 

 is tolerably constant in many groups, there are others, notably certain 

 sub-families of Textulariidce, in which it is by no means uniform. 



In the midst of the sandy mud which formed the bottom where 

 the warm area of the ' Globigerina mud ' abutted on that over which 

 a glacial stream flowed, there were found a number of little pellets, 

 varying in size from a large pin's head to a large pea, formed 

 of an aggregation of sand-grains, minute foraminifers, &c., held 

 together by a tenacious protoplasmic substance. On tearing these 

 open the whole interior was found to have the same composition, 

 and no trace of any structural arrangement could be discovered in 

 their mass. Hence they might be supposed to be mere accidental 

 agglomerations were it not for their conformity to the ' monerozoic ' 

 type previously described ; for, just as a simple ' moner,' by a differen- 

 tiation of its homogeneous sarcode, becomes an Amoeba, so would 

 one of these uniform blendings of sand and sarcode by a separation 

 of its two components the sand forming the investing ' test ' and 

 the sarcode occupying its interior become the arenaceous Astro- 

 rhiza. This type, which abounds on the sea-bed in certain localities 

 presents remarkable variations of form, being sometimes globular, 

 sometimes stellate, sometimes cervicorn. But the same general 

 arrangement prevails throughout, the cavity being occupied by a 

 dark-green sarcode, while the ' test ' is composed of loosely aggregated 

 sand-grains not held together by any recognisable cement, and has 

 no definite orifice, so that the pseudopodia must issue from inter- 

 stices between the sand -grains, which spaces are probably occupied 

 during life with living protoplasm that continues to hold together 

 the sand-grains after death. These are by no means microscopic 

 forms, the ' stellate ' varieties ranging to 0*3 or even 0*4 inch in 

 diameter, and the ' cervicorn ' to nearly O5 inch in length. 1 A much 

 larger form was found by Mr. Brady among the dredgings made 

 in the Faroe Channel (see his ' " Challenger " Report,' p. 242) ; 

 Syringammina appears, when complete, to have been a sphere about 

 an inch and a half in diameter ; owing to its large size the almost com- 

 plete absence of cement becomes very noticeable, for the fragile form 

 can scarcely support its own weight when taken out of the water. 



Later on another large and interesting type belonging to 

 the same group was obtained by Mr. Wood-Mason, late of the 

 Indian Museum, from the Bay of Bengal. 2 This has received the 

 generic name Masonella. The test consists of a thin sandy disc, 

 nearly half an inch in diameter, either flat or saucer-shape, with 

 a central chamber and simple or branched radiating tubuli open 

 at the periphery. 



The purely arenaceous Foraminifera are ranged by Mr. H. B. 

 Brady 3 (by whom they have been especially studied) under two 



1 See the description and figures of this type given by the Author in Quart. 

 Journ. Microsc. Sci. vol. xvi. 1876, p. 221. 



2 Ann. and Mag. Nat. Hist. 1889, ser. vi. vol. iii. p. 293, woodcuts. 



5 See his ' Notes ' in Quart. Journ. of Microcs. Sci. n.s. vol. xix. 1879, p 20, and 

 vol. xxi. 1881, p. 31. 



