132 



HAEDWICKE'S SCIENCE-GOSSIP. 



[JUxNE 1, 1S67. 



investigation of the living forms. The foraminifers 

 should be captured alive, and put into and bred in 

 household vivaria. I see no difficulty in any one 

 doing this who has leisure sufficient. The tanks, if 

 constructed something on the plan of Mr. Ward's 

 ingenious fern-cases, with the addition of a heating 

 or refrigerating chamber for the regulation of the 

 temperature of the water and air, might be made 

 suitable for the condition of any species, tropical or 

 arctic ; and indeed as some particular forms are 

 known to exist in great abundance in many of the 

 estuaries of our own coast, it would seem that such 

 species must be sufficiently hardy to withstand any 

 of the ordinary conditions of indoor reservoirs, and 

 certainly any one residing on the borders of such 

 estuarinc districts could have ample means for the 

 observation of such foraminifers under their proper 

 natural conditions. The most important points to 

 be settled are : 1. Whether the shell of the fora 

 minifer is formed piecemeal or lobe after lobe ; or 

 whether the whole mass of sarcode exists in an 

 unprotected condition, and exhibits segmentation 

 before the formation of, the enveloping shell. 2. 

 Whether spontaneous fission does or does not take 

 place. 3. How generation is effected, and whether 

 by one or more than one means. 4. What are the 

 characters of the germs or ova, and what the dif- 

 ferences in the young stages between the fry of 

 various species ? 



The little that is known, added to what we have 

 reason to believe, amounts to this conviction, that 

 the sarcode exudes freely as it increases in mass by 

 nourishment from every pore and orifice of the 

 foraminifer's enveloping case, the whole shell 

 being covered with a film of sarcodous flesh ; at a 

 suitable period the exuded sarcode gathers itself 

 up into an additional fleshy lobe, and assumes 

 a characteristic aud definite shape. On the obten- 

 tion of permanency of form, shell-secretion goes 

 rapidly on, and the new animal is encased in a 

 contiguous lobe to the previous shell. This view 

 acquires confirmation from the fact that the older 

 lobes have more layers of shell-matter than the 

 more recent ones. Eor example, the primary lobe 

 of a four-lobed shell will have four layers, the 

 second three, the third two, and the last one layer 

 of shell-matter shown in its transverse section. 

 Moreover, as a general rule old shells are thicker 

 than merely adult ones, and largeness of individual 

 dimensions and conditions of ample food-supply, 

 and their reverses, induce such modifications of the 

 stoutness of the shell-structure as are in further 

 harmony with this view. 



That some foraminifera are viviparous we also 

 know, because the larger chambers of some indi- 

 viduals have been seen full of the shelled young 

 in considerable stages of advance. But how these 

 young are liberated has never been witnessed, so 

 far as I kuow, by human eyes. Most probably their 



growth increases until disrupture of the parent shell 

 is effected ; but it is on such points that actual obser- 

 vation is so much required. The young forms in a 

 free state are also found commingled in the same 

 samples of sand and mud with the adults of the 

 same species, and we think it may be pretty safely 

 asserted that the second youngest stage of all the 

 compound forms is that of one lobe joined on to the 

 primary animal, and which condition would not 

 occur if the foraminifer were perfected in its mere 

 sarcodous growth, and segmented before the forma- 

 tion of its shell. 



Of the special habitats of the various species, 

 much knowledge has been obtained, and although 

 there are some seeming discrepancies in the con- 

 flicting statements of naturalists, the reconciliation 

 of many of them is assured. Eor example, Dr. 

 Wallich views certain forms as inhabiting the depths 

 of the ocean, and says he has netted through seven 

 hundred fathoms of sea-depth from the surface 

 without the capture of a single individual ; whilst 

 Major Owen, coming over the same sea, bags in 

 abundance by net-sweeping the surface. It ap- 

 pears, however, when the subject is closely looked 

 into, that the same species abound in the same 

 regions, and that the kinds found living at the 

 top of the sea are also found living at the bottom. 

 Moreover, the Doctor swept in the daytime, and 

 the Major at night. This much is certain, that 

 some forms of foraminifers are not free, but are 

 firmly attached to foreign bodies, and such parasitic 

 forms adherent to otolithes and stones having been 

 dredged up from the greatest depths, are decisive 

 proof of the residence and vitality of those organisms 

 under those abyssmal bathymetrical conditions. 

 As other forms have essentially creeping habits, 

 being found travelling over the stems and leaves 

 of seaweeds— along the tidal and laminarian zones, 

 we may fairly infer that in accordance with their 

 state of development, their attained size, the 

 thickness or thinness of their shells, and the 

 relative energy of their particular vitality, individuals 

 of even the same species may be met with exempli- 

 fying all the intermediate conditions between abso- 

 lute fixity, crawling, and free swimming. 



Here we must leave this most interesting subject, 

 with the hope that these few pages will have 

 encouraged higher motives than a desire for the 

 mere possession of so many slides of these exquisite 

 pelagic life-grains, and that future pages of 

 Science-Gossip may show the fruits of good work 

 done. S. J. Mackie, E.G.S. 



Suspended Judgment. — A truly wise man is so 

 fully sensible how little he knows, and what things 

 he once was ignorant of which he is now acquainted 

 with, that he is far enough from supposing'his own 

 judgment a standard of the reality of things. — 

 Baker "On the Polype." 



