June 1, 1S67-] 



HARDWICKE'S SCIENCE-GOSSIP. 



131 



individually distinct as to amount to little more 

 than a mere congeries of globules. 



Another branch of development of form goes off 

 in the direction of a purely circular arrangement, 

 as in the Cyclolinfe (fig. 129), and Nummulites ; 



Fig. 128. G. hirsute. 



Fig. 129. Cyclolina cretacea. 



whilst the straight line and circular systems are 

 compounded and compromised in such genera as 

 Frondicularia (fig. 130), and Cuneolina (fig. 131). 



ca^ 



Fig. 130. 

 Frondicularia annularis. 



._;. . 



Fig. 131. 

 Cuneolina pavonia. 



There is yet another division of developments as 

 important as those we have been considering, and 

 capable of permitting again all those modifi- 

 cations of lobation and ornamentation we have 

 previously witnessed under novel and different 

 circumstances. This division is that constituted by 

 the compound forms — that is, those in which the 

 development of the lobes takes place upon a 

 plurality of lines. The lobes may be added upon 

 two, three, or more axes, and these axes may be 

 straight, bent, or spiral ; and in each of these 

 cases the lobation and ornamentation may repeat 

 the wonderful variety characteristic of the simple 

 classes. In Biloculina (fig. 132) we have one lobe 



Fig. 132. 

 hiloculinu simplex. 



Fig. 133. 

 Triloculinu Auslriaca. 



Fig. 134. 

 T. nitida. 



merely adherent to the side of another; in 

 Triloculina, a third lobe is patched on to the side 

 (figs. 133, 134). In Spiroloculina (fig. 135) we have 

 many lobes alternately added; and in Quinquelo- 

 culina, .and others, we have other still more com- 

 plex arrangements. 



Amongst the most abundant genera and species 



of the compound division are those which make up 

 their lobation on a sort of chrysalis-like plan, such 

 as Bulimina, Chrysalidina, Uirigerim (figs. 130, 137, 

 138). 



Fig. 135. 

 Spiroloculina 

 canaliculata. 



Fig. 136. 



Bulimina 



pupoides. 



Fig. 13;. 

 Chrysalidina 



gradutu. 



There still remains another group to be noticed — 

 those which, the lobations being more or less er- 

 ratic, become confluent, as in Planorbulina larvata, 

 and ultimately in some cases produce amorphous 

 masses like those of aged specimens of Planor- 





■ 



$\ 



Fig. 138. 

 Ueigeriua pygmcea. 





Fig. 139. 

 Truntulina variabilis. 



bulina retinactilata. Of this nature possibly is the 

 recently discovered very remarkable fossil from the 

 lowest of all known fossiliferous rocks — the Eozoon 

 Canadense. 



Amongst the simple single-axis forms, even crops 

 up, as an example of erratic growth, Truntulina 

 variabilis (fig. 139). 



Such, then, is in the main the groundwork of 

 the classification of the foraminifera — a classifica- 

 tion based on the plans of arrangement of the lobes 

 or segmentation of the shell. The animal inhabitants 

 are treated as all alike, mere masses of jelly-like 

 flesh. It is evident that a classification founded 

 entirely on the disposition of the parts of the shell 

 cannot be a perfect one, and that considerable 

 modifications must at the least be engrafted on it 

 as the knowledge of the living structure of the 

 animals and of their modes of generation is acquired. 

 Now it is just this knowledge which is needed, and 

 it is the acquirement of this information that is an 

 open and fame-giving field for microscopists. Almost 

 all that has been done in the way of modifying the 

 primary basis of a purely shell classification has 

 been done by inductive reasoning upon general 

 considerations or microscopic examinations of shell- 

 structure. What is wanted is a regular systematic 



