30 



HARDWICKE'S SCIENCE-GOSSIP. 



dwarfed, and ouly one variety, the typical Globigerina, 

 bulloides, is represented. The living Globigerinae 

 from the tow-net are singularly different in appear- 

 ance from the dead shells we find at the bottom. 

 The shell is clear and transparent, and each of the 

 pores which penetrates it is surrounded by a raised 

 crest, the crest round adjacent pores coalescing into 

 a roughly hexagonal network, so that the pores 

 appear to lie at the bottom of a hexagonal pit. At 

 each angle of this hexagon the crest gives off a deli- 

 cate flexible calcareous spine, whichis sometimes four 

 or five times the diameter of the shell in length. The 

 spines radiate symmetrically from the direction of 

 the centre of each chamber of the shell, and the 

 sheaves of long transparent needles crossing one an- 

 other in different directions have a very beautiful effect. 

 The smaller inner chambers of the shell are entirely 

 filled with an orange-yellow granular sarcode ; and 

 the large terminal chamber usually contains only a 

 small irregular mass, or two or three small masses 

 run together, of the same yellow sarcode stuck 

 against one side, the remainder of the chamber being 

 empty. No definite arrangement and no approach 

 to structure was observed in the sarcode, and no 

 differentiation, with the exception of round bright- 

 yellow oil-globules, very much like those found in 

 some of the radiolarians, which are scattered ap- 

 parently irregularly in the sarcode. We never have 

 been able to detect in any of the large number of 

 Globigerina? which we have examined the least 

 trace of pseudopodia, or any extension in any form 

 of the sarcode beyond the shell. 



Major Owen has referred the Globigerina with 

 spines to a distinct species, under the name of 

 G. hirsuta. I am inclined rather to believe that all 

 Globigerinae are to a greater or less degree spiny 

 when the shell has attained its full development. 

 In specimens taken with the tow-net the spines are 

 very usually absent ; but that is probably on account 

 of their extreme tenuity ; they are broken off by the 

 slightest touch. In fresh examples from the sur- 

 face, the dots indicating the origin of the lost spines 

 may almost always be made out with a high power. 

 There are never spines on the Globigerina; from the 

 bottom, even in the shallowest water. Two or three 

 very marked varieties of Globigerina occur ; but I 

 certainly do not think that the characters of any of 

 them can be regarded as of specific value. 



There is still a good deal of obscurity about the 

 nature of Orbulina unicersa, an organism which 

 occurs in some places in large proportion in the 

 Globigerina ooze. The shell of Orbulina is spherical, 

 usually about '5 millimetre in diameter, but it is 

 found of all smaller sizes. The texture of the 

 mature shell resembles closely that of Globigerina, 

 but it differs in some important particulars. The 

 pores are markedly of two different sizes, the larger 

 about four times the area of the smaller. The larger 

 pores are the less numerous ; they are scattered 



over the surface of the 'shell without any appear- 

 ance of regularity; the smaller pores occupy the 

 spaces between the larger. The crests between the 

 pores are much less regular in Orbulina than they 

 are in Globigerina. ; and the spines, which are of 

 great length and extreme tenuity, seem rather to 

 arise abruptly from the top of scattered papillae 

 than to mark the intersections of the crest. This 

 origin of the spines from the papillae can be well 

 seen with a moderate power on the periphery of the 

 sphere. The spines are hollow and flexible ; they 

 naturally radiate regularly from the direction of the 

 centre of the sphere ; but in specimens which have 

 been placed under the microscope with the greatest 

 care, they are usually entangled together in twisted 

 bundles. They are so fragile that the weight of the 

 shell itself, rolling about with the motion of the 

 ship, is usually sufficient to break off the whole of 

 the spines and leave the papillae only projecting 

 from its surface in the course of a few minutes. In 

 some examples, either those in process of develop- 

 ment, or a series showing a varietal divergence from 

 the ordinary type, the shell is very thin and almost 

 perfectly smooth, with neither papillae nor spines> 

 nor any visible structure, except the two classes of 

 pores, which are constant. 



The chamber of Orbulina is often almost empty ; 

 even in the case of examples from the surface, which 

 appears from the freshness and transparency of the 

 shell to be living, it is never full of sarcode ; but it 

 frequently contains a small quantity of yellow 

 sarcode stuck against one side, as in the last chamber 

 of Globigerina. Sometimes, but by no means con- 

 stantly, within the chamber of Orbulina there is a 

 little chain of three or four small chambers singu- 

 larly resembling in form, in proportion, and in 

 sculpture, a small Globigerina ; and sometimes, but 

 again by no means constantly, spines are developed 

 on the surface of the calcareous walls of these inner 

 chambers, like those on the test of Globigerina. 

 The spines radiate from the position of the centre 

 of the chambers and abut against the insides of the 

 wall of the Orbulina. In a few cases the inner 

 chambers have been observed apparently arising 

 within or among the sarcode adhering to the wall 

 of the Orbulina. 



Major Owen regards Orbulina as a distinct organ- 

 ism, nearly allied to Globigerina, but differing so 

 far from it as to justify its separation into a special 

 subgenus. He considers the small inner chamber 

 of Orbulina as representing the smaller chamber of 

 Globigerina, and the outer wall as the equivalent of 

 the large outer chamber of Globigerina developed 

 in this form as an investing chamber. Count 

 Pourtales, Max-Schultze, and Krohn, on the other 

 hand, believe, on account of the close resemblance 

 in structure between the two shells, their constant 

 association, and the undoubted fact that an object 

 closely resembling a young Globigerina is often 



