266 PEOCEEDINGS OF SOCIETIES. [-Turall, MayTim' 



In Saccamina " the test is of very regular spherical form, with a 

 flask-shaped neck, and it is composed of large sand-grains firmly 

 cementecl together so as to present a smooth exterior, whilst their 

 angles project into the interior of the cavity, which is filled with living 

 sarcode." In Pilulina the form of the test is spherical, but it dificrs 

 from Saccamina in its mouth being "a somewhat sinuous flexiu'e," and 

 being composed of extremely fine white sand-grains, worked up with 

 the pointed ends of sponge-spicules. The specimens of this type 

 shown by Dr. Carpenter " were brought up alive from 1215 fathoms." 

 " The test of Rhahdammina is usually trii-adiate, having a central 

 cavity which extends itself to the open end of each of the radiating 

 tubes ; and it is composed of quartz sand-grains, fii'mly united together 

 by a cement which contains a large proportion of phosphate of ii'on." 



The Pro^eonmn present a very curious difference in their materials, 

 which seems to depend upon the character of the bottom from which 

 they were resj)ectively obtained. Where this consists of nearly pure 

 globigerina, and having sjjonge-spicules dispersed through it, but 

 scarcely any admixtiu'e of sand, the animal builds up its test of sponge- 

 spicules, only using a grain of sand here and there to fill up a corner 

 left by the crossing of the sponge-spicules. But where the bottom 

 abounds in sand-grains, the animal uses them as the materials of its 

 test, still, however, using sponge-spicules for the prolongation which 

 forms the mouth at each end, this prolongation being sometimes ex- 

 tended like a proboscis : found at a dej)th of 650 and 540 fathoms. 



Concerning the Porcellanous Foraminifera of the Deep-Sea Dredg- 

 ings, Dr. Carpenter remarks that " the MiliolincB brought up from 

 great depths are remarkable for their great size ; no larger specimens 

 of Cornuspira, BilocuUna, and Triloculina being known than those here 

 exhibited." 



Fragmentary specimens of Orhitolites seemed to indicate that the 

 entire disk must often attain the size of a sixpence. " The nucleus of 

 this disk is fonned by a spire of several turns, precisely resembling the 

 central part of a Cornuspira : by the opening out of the sj)ii'e, and the 

 subdivision of its cavity into chamberlets, the first approach is made 

 to the cyclical arrangement characteristic of the Orbitolite ; and the 

 whole subsequent growth takes place on the cyclical plan. Each 

 ring contains an annular gallery, communicating with every one of 

 the chamberlets ; the outer side of this gallery gives off passages 

 which lead into the chamberlets of the next ring; and the passages 

 thus given off from the marginal ring open as pores on the surface, 

 and constitute the only channel of communication between the entire 

 system of galleries and chamberlets to the exterior." 



Dr. Carpenter observes of the Vitreous Foraminifera that the 

 " GlohigerincB and Orbulince, of which an accumulation covers a large 

 proportion of the North Atlantic sea-bed to an unknown thickness, 

 fonned a deposit closely resembling chalk. These types occur at all 

 dej^ths, from 200 or 300 fathoms to three miles." 



In addition to the above, Dr. Carpenter exhibited a series of 

 Cristellarice, sho'ttnng every gradation from the straight to the nauti- 

 loid foi-m ; also the animal of Cristellaria, obtained by dissolving the 



