June 29, 1«83.J 



KNOWLEDGE ♦ 



389 



as over-reaching himself, and as befooled by mortals. And, 

 like the Trolls of Soaiulinavian folklore who burst at sun- 

 rise, it needed only tlic full light thrown upon his origin 

 and development by the researches of comparative mytho- 

 logists to dissipate this creation of man's fears and fancier 

 into the vaporous atmosphere where lie liad his birth. 



THE FISHERIES EXHIBITION. 



NATCEAL HISTOKY DEPARTMENTS. 

 By John Ersest Ady. 



rpHE student of natural science will search in vain for 

 JL an adequate representation of the class Jihizopoda 

 amongst the extensive collections in the Exhibition ; yet 

 the members of this group play so important a part, not 

 only as food and as atl'ecting the conditions of existence of 

 all kinds of fish, but also in the structure of the crust of 

 the earth in times past and present, that a general record 

 of some of the facts connected with their systematic 

 position and life-history ought to find a place here. 



It is now some years since Huxley gave the name BatJuj- 

 bius to what he then belisved to consist of irregular, form- 

 less masses of protoplasm diffused over the lloor and at 

 great depths of the sea, and, more recently, Bessels de- 

 scribed a similar structure under the name I'rotobathybins. 

 The reports of the ChnHprnjiT naturalists have taught us 

 that, even at enormous depths, the conditions are not in- 

 compatible with the existence of highly -organised forms of 

 life ; the question then naturally arises. What do these 

 creatures live upon ? The ready answer would be Batluj- 

 bius .' During the cruise of the CliaUeuijer, Murray was 

 struck with the development of a material, in the bottles 

 of spirit into which specimens had been dropped freshly 

 after capture, and which strongly called to mind 

 Huxley's Bathyhius ; the material was not there at first, 

 but accumulated with time. This led him to make a few 

 experiments, and to discover that a natural process of 

 chemical precipitation was going on in the sea whereby a 

 gelatinous product, similar to that which was collecting 

 artificially in the bottles of spirit, resulted in the proto- 

 plasmoid substance Batlqjhiut!, which, on chemical analysis, 

 was shown to consist of sulphate of lime. AVe can scarcely, 

 however, credit Herdnian's unique Abijssasriilia WyviUii* 

 which was brought to light from a depth of 2,600 fathoms, 

 with the faculty of deriving sustenance from a gelatinous 

 pi-ecipitate of pure sulphate of lime. Doubtless there are 

 primitive forms of life, belonging to the lihhopoila, which 

 contribute to the bodily wants of the abyssal fauna. 



In our description of the Amctha, we chose a typical 

 example {Amo:ba princeps) wherewith to illustrate the 

 structure and life-history of the group. It now remains 

 to be added, that such a form as AmrKba may pass into one 

 in which the pseudopodial area becomes restricted {Patn- 

 })haf/i(s), or it may develop a firm membraneous carapace 

 (ArceUa), or the carapace thus formed maybe strengthened 

 with adventitious particles, such as grains of sand, itc, 



(Difflurjia). 



This naturally leads to the next order of the Rhizopoda, 

 viz., the Foraminiftra ; where, in addition to the structures 

 enumerated in th^ Amaba, the forms are characterised by 

 the presence of an arenaceous, chitinous, or, more com- 

 monly, a calcareous test, often of great beauty, and, which 



* Proc. Koyal Soc. Edin., 1879-80, p. 4T0. 



we noted before, plays an important part in the formation 

 of the earth's crust. 



The Foraminih-ra, with but few exceptions {e.g., Gromia, 

 which is found in both fresh and salt water), inhabit the 

 sea, and all the known recent forms are of microscopical 

 dimensions. In ancient times, however, they attained 

 relati\ely gigantic proportions, as in the Eocene XunDmi- 

 litcs, which in days gone by were stated by certain learned 

 persons to be the remains of an ancient Egyptian currency. 

 These Nummulites are often an inch in diameter, and the 

 Cretaceous rarhria is sometimes twice that size. In still 

 remoter times, in fact, in the most ancient formations of the 

 geological record, the Laurentian rocks of Canada, a curious 

 structure has been described as a gigantic Foraminifer, 

 under the name of Eozoon Canailense. A great deal of 

 dispute has arisen respecting the true nature of Eozoon ; 

 it has been claimed by petrologists as of inorganic origin, 

 and is said by them to be the mere metamorphosed results 

 of a purely mineral aggregate or rock. The dispute has 

 not, by any means, been satisfactorily settled, and it w ould, 

 therefore, be out of place for us to enter into any detailed 

 account of it here. Sutlice it to say that similar structures 

 have been observed in several of the so-called marbles and 

 serpentines of the continent of Europe, and also quite 

 recently by Heddle in Sutherlandshire.* 



If to tlie body of an A ma ha, devoid of any distinct 

 separation into ecto- and endo-pla,<m, we add a delicate sub- 

 external shell, composed of a horny or calcareous material, 

 perforated in such a manner as to permit the escape of its 

 pseudopodia, and provided with spines, we shall then have 

 a typical Foraminifer. The shell is generally pierced by a 

 number of minute pores, or may contain but one large 

 terminal aperture ; through these the pseudopodia, which 

 are generally filamentous and interlacing protrude, and a 

 thin layer of the protoplasm of the body, moreover, forms 

 a superficial stratum over the surface of the test. The 

 protoplasm of the body is usually of a bright yellowish 

 hue, and exhibits a peculiar circulation of granules, 

 analogous to that which may be observed in certain 

 plants, t 



In accordance with the perforation of the walls of their 

 tests, Foramini/i ra have been divided into two great 

 groups, the Perforata and Impcrforata. The nature and 

 form of the shell was long accepted as the foundation on 

 which the classification of this interesting group was based, 

 whilst the more important factors in their development 

 were disregarded, because they were not imderstood ; now 

 that they have been partially revealed, the artificial classi- 

 fication promulgated by Max Schultze has given place to 

 others more in accordance with observed facts, and the 

 natural systems of Reuss and of Carpenter, Parker, and 

 Rupert Jones, are now generally in vogue. The latter 

 divides all Foraminifera thus : — 



I " i ^1 I I I 



GromiJa. Millioliila. LiltioUda. Lngenida. Olobigcrinlda. ItummuUnida. 

 (To he continued.) 



* Professor Heddle's report on the rock has not yet been pub- 

 lished, but will appeal- shortly in the Mineralo'jical Magazine. — 

 J. E. A. 



t We may here draw the attention of the reader to Mr. Bolton's 

 table, stand 756, once more. Under one of the microscopes he will 

 notice a specimen of the proombryo of Nittllu, showing the circu- 

 lation alluded to above. — J. E. A. 



