1922] Proceedings of the Academy of Science 9 



with the means of attacking geometric situations by means of analysis. 

 It is now one of the problems of the mathematician to adapt to a 

 problem that particular system of coordinates best suited to it. In 

 trying to do this many kinds of coordinate systems have arisen. One 

 of these, namely homogeneous coordinates, besides possessing marked 

 power in itself, includes many of the more frequently used systems 

 as particular cases. A detailed and connected account of this system 

 is a need keenly felt by students of mathematics. This paper points 

 out this need, and suggests lines along which this account may be 

 developed. 



A Note on the Puhnonary Circulation in Vertehrates. W. C. George. 

 Some anomalies in the pulmonary veins of man were described. 

 Attention was called to the correspondence between the atypical con- 

 dition in these anomalies and the typical relations of the vascular 

 drainage of the air-bladders of some tishes. 



Notes on Protozoa. Bert Cunningham. 



The report consisted of two parts. The first was a systematic 

 study of the forms occurring near Durham. The following classes 

 and orders were observed : 



Class Ehizopoda 29 



Order Gymnamoebida 5 



Testacea 2-4 



Class Actinopoda 2 



Order Aphrothoracida 2 



Class Zoomasiigophora 18 



Order Monadida 1 



Phytomastigida 2 



Euglenida 11 



Dinif erida 4 



Class Ciliata 44 



Order Holotricha 19 



Heterotricha 12 



Hypotricha 8 



Periotricha 5 



Class Phytomastigophora 3 



Order Chrysoflagellata 1 



Chloroflagellida 2 



96 96 



