8l8 MICROSCOPIC FORMS OF ANIMAL LIFE 



chamberlets, instead of being arranged in successive rings on a single 

 plane, so as to form a disc, are grouped in concentric spheres, each 

 completely investing that which preceded it in date of formation. 

 The outer wall of each chamberlet is itself penetrated by extensions 

 of the cavity into its substance, as in the Cyclamminal&si described; 

 and these passages are separated by partitions very regularly built 

 up of sand-grains, which also close in their extremities, as is shown 

 in fig. 618. The concentric spheres are occasionally separated by 

 walls of more than ordinary thickness, and such a wall is seen in 

 fig. 617 to close in the last-formed series of chamberlets. But these 



walls have the same ' labyrinthic ' 

 structure as the thinner ones, 

 and an examination of numerous 

 specimens shows that they are 

 not formed at any regular inter- 

 vals. The ' nucleus ' is always 

 composed of a single series of 

 chambers arranged end to end, 

 sometimes in a straight line, as 

 in fig. 617, c 1 , c 2 , c 3 , c 4 , sometimes 

 forming a spiral, and in one in- 

 stance returning upon itself. 

 FIG 618.-Portion of one of the lamella fi t th outermost chamber en- 

 of Parkena, showing the sand-grams of , .. ., . , .. _ 



which it is built up, and the passages larges, and extends itself over the 

 extending into its substance. whole ' nucleus,' very much as the 



' circumambient ' chamber of the 



Orbitolite extends itself round the primordial chamber ; and radial 

 prolongations given off from this in every direction form the first 

 investing sphere, round which the entire series of concentric 

 spheres are successively formed. Of the sand of which this remark 

 able fabric is constructed about 60 per cent, consists of phosphate of 

 lime, and nearly the whole remainder of carbonate of lime. Another 

 large fossil arenaceous type, constructed upon the same general plan, 

 but growing spirally round an elongated axis, after the manner of 

 Alveolina (fig. 608), and attaining a length of three inches, has been 

 described by Mr. H. B. Brady (loc. cit.) under the name Loftusia, after 

 its discoverer, the late Mr. W. K. Loftus, who brought it from the 

 Turko-Persian frontier, where specimens were found in considerable 

 numbers imbedded in ' a blue marly limestone,' probably of early 

 Tertiary age. 



There is nothing, it seeing to the Author, more wonderful in 

 Nature than the building up of these elaborate and symmetrical 

 structures by mere 'jelly-specks,' presenting no trace whatever of 

 that definite ' organisation ' which we are accustomed to regard as 

 necessary to the manifestations of conscious life. Suppose a human 

 mason to be put down by the side of a pile of stones of various shapes 

 and sizes, and to be told to build a dome of these, smooth on both 

 surfaces, without using more than the least possible quantity of a 

 very tenacious but very costly cement in holding the stones together. 

 If he accomplished this well, he would receive credit for great in- 

 telligence and skill. Yet this is exactly what these little ' jelly-specks ' 



