HARDWICKE'S SCIENCE-GOSSIP. 



13 



finally emerging as the exhalent currents of the 

 oscula. These currents are maintained by the 

 lashing movements of flagella which line the walls 

 of the enlargements just mentioned. 



To recapitulate. The fundamental structure of this 

 sponge is as follows — it is composed of a sponge-flesh 

 supported by a skeleton. The latter is composed of 

 a network of delicate needles, gathered into inter- 

 lacing bundles ; the former, that is the sponge-flesh, 

 forms a mass which contains imbedded in it the 

 skeleton, and is also honeycombed by a system of 

 canals and spaces, all in complete intercommunica- 

 tion, the canal system. One extreme of the canal 

 system is the pores, the other the oscula ; and through 

 it a continual stream of water is flowing during the 

 life of the animal setting from the pores to the oscula. 

 This current is maintained by the action of flagella 

 situated on the cells lining certain enlargements in 

 the course of the canals, known as the "flagellated 

 chambers." 



The further anatomy of the sponge-flesh now 

 remains to be dealt with under the heading histology. 

 A more complete account of the canal system will 

 then be given, and the sketch of the anatomy of 

 Halichondria panicca will be complete. 



W. B. Hardy, B.A. 



GOSSIP ABOUT FORAMINIFERA. 



Part i. 



By Edward H. Robertson. 



IF the reader be a microscopist, hath it ever 

 occurred to him what manifold advantages he 

 possesses over his tr^wymrj, the geologist, the botanist, 

 the physiologist, and the zoologist ? If not mere 

 systematists, the abounding delights of their several 

 pursuits may, and do, charm them into enthusiasm ; 

 but there occur times and seasons when even their 

 engrossing pleasures must, for obvious reasons, be 

 laid aside or neglected. 'Tis never so with the 

 genuine microscopist, for altogether independent of 

 time or season — excepting in the case of serious 

 illness — instrument in hand, he may, at his own 

 sweet will, wander through Nature's unbounded 

 realm, gleaning in every sweet field, and from even 

 the most neglected corners and arid deserts, marvels 

 of beauty to call forth his admiration and delight. 

 Imprison him in a lonely cell and leave him but his 

 microscope, and I trow he will have no cause to 

 lament a lack of beauty within even its narrow 

 confines. Nay, more, remove from its case the 

 works of that triumph of human skill and con- 

 trivance, a watch, and tell him to accomplish the 

 seemingly impossible task of filling its empty com- 

 pass with a store of marvels that would require a 

 life-time to examine, and it shall be done. 



Smile not, reader — this is no exaggerated metaphor 

 — 'tis a literal fact, and I repeat more fully that, if 



he were to devote every moment of a long life to the 

 study of the minute organisms that might be con- 

 tained within the compass of an ordinary watch case 

 — his thread of life would be severed in the very 

 midst of his pleasant labours. And yet, haply, liis 

 treasures might consist solely of the very humblest 

 forms of animal and vegetable life — foraminifera, 

 polycystina, and diatomacese. 



If the longest span of human existence would be 

 inadequate to examine in detail his countless treasures, 

 how many volumes would he not require in which to 

 record his observations? How, then, shall the 

 writer, within the small compass of a few columns 

 in Science-Gossip, hope to convey more than the 

 barest notion of one of the groups referred to ? I 

 shall not attempt so herculean a task, so well 

 performed by students infinitely more capable than 

 I, but shall content myself with ;a .brief sketch of 

 one of these three groups — the Foraminifera. In doing 

 this, I wish to be regarded rather as a recorder, than 

 as an expounder of certain curious facts with which 

 the history of these wonderful and minute organisms 

 abounds. When we commence our examination of 

 them, we at once plunge into an infinitude of beauty, 

 and are lost in wonder and admiration at their 

 extraordinarily varied and graceful forms, often sur- 

 passing in symmetry the most costly productions of 

 ceramic art. Yet, notwithstanding the beauty of 

 their external coverings, would it ever have entered 

 into the belief of the uninstructed that the inhabitants 

 of these same beautiful structures are but homo- 

 geneous atoms of jelly, exhibiting no more definite 

 organisation or structure than does the drop of glue, 

 being even destitute of any. investment? Yet such is 

 indeed the case. These foraminifera occupy a place 

 amongst the humblest forms of animal life, and are 

 classed by naturalists with the Rhizopoda, that class 

 of lowly organisms in which are placed the sponges, 

 amcebK, polycystina, etc. 



The class Rhizopoda is one of the three great 

 groups into which the sub-kingdom. Protozoa (Gr.) 

 protos, first ; zodn, animal), is divided, and derives its 

 name from two Greek words, rhiza, root, and pons, 

 foot, from the fact of all the animals included in it 

 possessing the power of throwing out, from the 

 surface of any part of their body, processes termed 

 " pseudopodia " (Gr. pseudos, falsity, and pons, a 

 foot) which they employ in moving about and in 

 obtaining food. Unlike the feet and arms of more 

 highly- organised animals, these pseudopodia can be 

 again withdrawn or absorbed into the substance of 

 the body, leaving not a trace behind. This jelly-like 

 protoplasm is termed "sarcode" (Gr. sarx, flesh, 

 and eidos, form), and is a gelatinous, somewhat 

 granular substance, resembling thin glue, or the 

 white of egg. 



As already stated, this substance exhibits no definite 

 organisation, or structure, "so that," to quote the 

 words of Dr. Carpenter, " the physiologist has here a 



