ON THE LIFE-HISTORY OF THE FORAMINIFERA. 179 



Calcarina hispida, 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/xXll|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. x56. Another specimen of the microspheric form. The 

 inner chambers are not represented. The microsphere measured about 

 15 ;i X 12-5 fi. The later chambers contain numbers of young, presumably 

 megalospheric, forms. 



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

 in fig. 36, with its contents. 



Rotalina Beocarii, Linn. 



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

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

 in the inner chambers. 



Fig. 39. X 170. Megalospheric form. Twenty-four chambers are 

 present. The megalosphere measures 45 ji* x 40 /x. A single large nucleus 

 is contained in the eighth chamber. 



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



Orbitolites complanata, Lamk. 

 Microspheric form. 



Fig. 41. x760. Section through the contents of a " chamberlet." 

 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 nuclear 

 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 brood-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, hsematoxylin. 



