384 THE MICROSCOPE. 



tion. One globular species appears like a specimen of the 

 Chinese ball-cutting — one spbere within another ; but it 

 is of a marked and distinct kind. 



"The shells of some of the globular forms of these 

 Polycystina, whose conjugation I believe I have witnessed, 

 are composed of a fine fretwork, with one or more large 

 circular holes ; and I suspect the junction to take place 

 by the union of two such apertures. That the figures of 

 these shells become elongated, lose tbeir globular form 

 after death, and present a disturbed surface is seen in 

 some of the figures represented near the bottom part of 

 Plate III." Major Owen proposes to make Orbulina a 

 subgenus of Globigerina. The internal chambers of the 

 former are in form remarkably like those of the latter, 

 and like them also they present themselves with varying 

 surfaces, some free from, while others are covered with, 

 spines. Those without internal chambers have been 

 known as Orbulina universa, fig. 78, Plate III. while 

 figs. 75 and 76, although members of the same family, 

 have been separated ; but he wishes to see all united under 

 the name of " Globigerina universa" 



The minute siliceous shells of Polycystina present won- 

 derful beauty and variety of form ; all are more or less 

 perforated, and often prolonged into spines or other pro- 

 jections, through which the sarcode body extends itself 

 into pseudopodial prolongations resembling those of Acti- 

 nophrys. When seen besporting themselves in all their 

 living splendour, then brilliancy of colouring, says Major 

 Owen, "renders them objects of unusual attraction." We 

 have endeavoured to give some idea of the colour of the 

 living forms in Plate III. Nos. 43 to 52. The same ob- 

 server believes that they wish to avoid the light, " as they 

 are rarely found on the surface of the sea in the day time ; 

 it is after sunset, and during the first part of the night 

 especially, that they make their appearance." 



The Polycystina appear to have most affinity with the 

 Foraminifera. Thirty four genera and about two hundred 

 and ninety species have been described. They are most 

 abundant in the fossil state ; and are very plentiful in the 

 rocks of Bermuda, in the tripoli of Richmond, Virginia, in 

 the marls of Sicily, and other places. Their minute sheila 



