910 SUMBIARY OF CURRENT RESEARCHES RELATING TO 



the present, and it has an elaborately compiled bibliography. The 

 various classifications of the Ehizopods, from that of Dujardin in 

 1841 to that of Leidy in 1879, are glanced at. More details are given 

 as to the various attempts at classifying the Foraminifera, and the 

 author proposes a scheme differing in many respects, and often widely, 

 from those given by previous writers, but one which, in its essential 

 elements, is in no way incompatible with the different conclusions at 

 which they had arrived. The nature of the investment of the animal 

 — that is to say, the minute structure of its test — as an exclusive 

 basis for the primary divisions of the order has been abandoned. 

 While under all circumstances it furnishes important characters, and 

 is even in some families quite distinctive, it is nevertheless a fact that, 

 whilst there are certain groups which are invariably arenaceous, and 

 some which are always calcareous and perforate, there are yet others 

 in which no uniform rule obtains. The author omits any division of 

 the order into sub-orders, not finding any easily recognized characters 

 to serve as a basis for such subdivision, and he divides the order at 

 once into families. These families are (1) Gromidse, (2) Miliolidse, 

 (3) Astrorhizid^, (4) Lituolid^, (5) Textularidse, (6) Cheilostomidaa, 

 (7) Lagenidae, (8) Globigerinidse, (9) Eotalidse, (10) NummulinidaB. 

 The Gromidse, a family composed chiefly of fresh-water organisms, 

 " have been a source of considerable trouble, on account of the want 

 of accuracy and detail in the published descriptions of a number of 

 types more or less closely allied to the group, and only such 

 genera have been included as are known to have long, reticulated 

 pseudopodia." 



One of the most interesting subjects in reference to deep-sea 

 deposits is their direct connection with the pelagic species of Forami- 

 nifera. As a rule these forms are not of pelagic habit ; on the 

 contrary, probably 98 or 99 per cent, of the known species or varieties 

 live in the sand or mud of the sea-bottom, and possess no powers of 

 floating or swimming ; but, on the other hand, some few forms, 

 belonging to eight or nine genera, do most certainly pass their 

 existence either in part or in whole at the surface of the ocean, or 

 floating at some depth below that surface. These forms are found, 

 too, in immense profusion, and a relatively very large mass of the 

 oceanic deposits consist of their calcareous shells. A list of the at 

 present ascertained pelagic forms is given. The most prominent 

 genera are Glohigerina, Pulvinulina, Hastigerina, and Pullenia. The 

 question seems still unsettled as to whether the species are exclusively 

 pelagic, passing the whole of their time living at or near the surface,- 

 or whether they can or do pass a certain portion of it on the sea- 

 bottom. Mr. Brady adduces a series of facts which tend to the 

 inference that the Foraminifera which are found living in the open 

 • ocean have also the power of supporting life on the surface of the 

 bottom-ooze, and further, so far as our present knowledge goes, there 

 is at least one variety of the genus Glohigerina which lives only at 

 the sea-bottom ; but the author is most cautious not to express any 

 dogmatic opinion on the subject. 



In dealing with the composition of the test, the presence of a 



