127 



Addendum to the foregoing Paper. 



Appendix A. — Since the preceding pages were penned, my friend 

 Dr. Baird, of the British Museum, the enlightened historian of the 

 British Entomostraca, has shown me two or three specimens 

 brought by Sir Edward Belcher from Borneo, which appear to 

 belong to this group of the Foraminifera. One of these was two 

 inches and a quarter in diameter, reminding us of the splendid spe- 

 cimen of Orbitoides brought from Alabama by Sir Charles Lyell. 

 Some of Mr. Jukes' Australian specimens in the possession of Dr. 

 Carpenter are half an inch in width : these, however, are but the 

 exceptions ; as a rule, the recent species are of diminutive size 

 when compared with the magnificent forms characterizing the rocks 

 of the Nummulitic era, both in the old and new worlds. 



Appendix B. — Through the kindness of Dr. Carpenter I have 

 been enabled to compare my specimens with those of Mr. Jukes. 

 In these most of the superficial fossae are covered over by a thin 

 film of calcareous substance, as is the case with the cells of Orbi- 

 culina adunca. This circumstance has led me to re-examine my 

 Tongese specimens ; and I find that though they are almost all in 

 the condition described in the text, and delineated in figs. 12 and 13, 

 here and there traces of a similar calcareous film may be detected ; 

 showing that its presence constitutes the normal condition. Its dis- 

 appearance has apparently resulted from mechanical influences of the 

 surf beating upon the shore, since in the Tongese examples the dif- 

 ferences of age and size do not appear to affect the existence or 

 otherwise of this superficial covering of the fossae. 



February 27, 1851. 



