ON THE LIFE-HISTORY OF THE FORAMINIFERA. 179 



Calcarinu /u'spida, Brady. 



Fig, 34. X 250. The inner chambers of a specimen of the megalo- 

 spheric form with seventeen chambers. The nucleus is seen in the fourth 

 chamber, sending a process into the fifth. 



Fig. 35. X 250. Inner part of a specimen of the microspheric form 

 with thirty-nine chambers. The microsphere is 13/iXll/i in diameter. 

 The specimen is ill-preserved, but indications of five nuclei can be detected 

 in some of the chambers which follow those here represented. 



Fig. 36. X 56. Another specimen of the microspheric form. The 

 inner chambers are not represented. The microsphere measured about 

 15 ^x 12-5 /i. The later chambers contain numbers of yoimg, presumably 

 megalospheric, forms. 



Fig. 37. X 250. Part of one of the chambers of the specimen shown 

 in fig. 36, with its contents. 



Rotalina Beccarii, Linn. 



Fig. 38. X 170. Microspheric form. Thirty -three chambers are 

 present. The microsphere is 13 /n in diameter. Many nuclei are contained 

 in the inner chambers. 



Fig. 39. xl70. Megalospheric form. Twenty-four chambers are 

 present. The megalosphere measures 45 /n x 40 /;». A single large nucleus 

 is contained in the eighth chamber. 



Fig. 40. X 460. The nucleus of another megalospheric specimen. 



Orhitolites complanata, Lamk, 

 Microspheric form. 



Fig. 41. X 760. Section through the contents of a " cha,mberlet." 

 The rounded nuclei are seen to be disposed in pairs. A nucleus is in 

 process of division, the two halves being connected by a constricted band. 

 Alcohol, picro-carmine. 



Fig. 42. X 760. Three of the larger nuclei of this form. The luiclear 

 reticulum is distinctly seen. Alcohol, picro-carmine. 



Fig. 43. X 38. Vertical radial section through the margin of the disc 

 of a fully-grown specimen. As is usually the case in the microspheric 

 form of the variety laciniata, the margin is double, hence the section is 

 Y-shaped. The more central part of the disc is represented only by the 

 organic basis of the walls of the chamberlets. In the peripheral portions 

 the large hrood-chambers are seen crowded with young. Alcohol, hsema- 

 toxylin. 



Fig. 44. X 56. Vertical tangential section through the margin of 

 a disc whose brood-chambers contain young. Alcohol, haematoxylin. 



