252 Rhodora [Novbmbub 



had living material from these four stations and from the three 

 European stations for simultaneous examination, and after careful 

 study am convinced that it all belongs to one species I had hoped to 

 find at Plymouth the type species.. PJutyvimuis frirathclc West, hut I 

 could only discover there P. subcordiformis and a new species, quite 

 different from either, which I had also found at Aalesund. 



It may appear strange that the compressed form of the cell, which 

 is the chief character upon which this species is to he placed in the 

 genus Plaiymonm rather than in Carfrria, was overlooked by Wille. 

 But at certain times the narrower diameter of the cells is so little 

 presented to view as to he very inconspicuous. My own first im- 

 pression was that this species exhihited hardly sufficient differences 

 to warrant its removal from the genus Cartcria, hut extended observa- 

 tion during more than a year has convinced me that it is very distinct, 

 and that it is very desirable to maintain the genus Plaiymonas West. 

 Wille has also recorded Catieria svbcordiformu as a freshwater species, 

 while in all the seven stations where I have collected it the water has 

 been brackish; but. in these small rock hollows on the shore the salinity 

 of the water undoubtedly varies considerably. I have found that 

 cells may be transferred successfully to fresh water or to clean sea 

 water. — Tracy E. Haze.v. 



ASTEROCOCCUS STJPERlirs (Cienk.) Seherf.— This beautiful member 

 of the Protococcalcs was found in abundance in 1920 and 1921 among 

 sphagnum along the shores of Sheep Pond, Cuttyhunk Island. This 

 is its first recorded occurrence for North America, though Smith 1 has 

 found Asterococcus limnetic us in Wisconsin. 



The method of escape of the spores, not hitherto noted, is indicated 

 in fig. 2(5. The lamellae at a point opposite the clear spot which is the 

 point of origin of the cilia soften and swell, finally dissolving. The 

 outermost layer is first involved, then the others progressively until the 

 spore is free to escape. — I. F. Lewis. 



Anahaena spiroides var. crassa Lemm— On July 30, 1920, the 

 writer noted a considerable "bloom" on North Head of Hummock 

 Pond, Nantucket, Massachusetts. This on examination proved to be 

 a mixture of Clathrocystis aeruginosa (Kilts) Henfr., and an Anabaena 

 notable for the regularity of its spiral triehome, and for having round 



1 Smith, O. M. Pliyt.oplankl.on of the inland lakos of Wisconsin. Madison. 1020. 



