180 J. J. LISTER. 



Megalospheric form. 



Fig. 45. X 120. Young specimen, decalcified. The centre is occupied 

 by the "primitive disc," consisting of the "primordial chamber" (megalo- 

 sphere) and the "circumambient chamber." Some six rings of chamberlets 

 have been formed. 



Fig. 46. X 540. Section of the nucleus of a very young specimen 

 recently libei-ated from the brood-chambers of the parent. Hsema- 

 toxylin. 



Fig. 47. X 760. Section of nucleus of a specimen with about twenty- 

 .six rings of chamberlets. Hsematoxylin. 



Fig. 48. X 760. Section of the primordial chamber of a specimen 

 with about thirty rings of chamberlets, showing the nucleus. Small algae 

 and starch grains are contained in the protoplasm. Hsematoxylin. 



Fig. 49. X 415. Section of the primordial chamber of a specimen in 

 which the nucleus appears to have broken up into irregular fragments. 

 About twenty-five rings of chamberlets had been formed. Picro- 

 carmine. 



Fig. 50. X 6. Part of the disc of a specimen bearing young in its 

 brood-chambers. Decalcified. P.c?. (primitive disc.) The protoplasm has 

 left the part of the disc internal to the brood-chambers. 



Fig. 51a. X 38. The young contained in the brood-chambers of the 

 same specimen. 



Fig. bib. x38. One of the young removed from the brood-chambers. 

 The spaces from which the shell has been dissolved are seen dividing the 

 protoplasm. 



Fig. 51c. X 38. The empty primitive disc of the parent shell. The 

 walls have shrunk owing to the action of the i-eagents. 



Cycloclypeus Carpenteri, Beady. 



Fig. 52. x56. The chambers occupying the centre of a specimen 

 measuring about 1 centim. in diameter : M. the megalosphere ; (2) the 

 large second chamber containing, in this instance, the nucleus. The 

 nucleus measures 85 y. in diameter. 



Fig. 53. Some of the chambers of a decalcified specimen, showing 

 the somewhat irregular arrangement of the connecting canals. 



Fig. 54. x460. Section of the nucleus of another specimen. In 

 this ca.se the nucleus was in the megalosphere. It measures 60 /it x 40 /x. 



