506 SUMMARY OF CURRENT RESEARCHES RELATING TO 



It was discovered in an old algal culture which had been for a year in 

 the greenhouse, as well as in a puddle after rain. It varies in size 

 from 7-9 /x, is curved, and resembles the spermatozoids of Chara, ferns, 

 etc. The movements may be slow and irregular, quick and gliding, or 

 jerky. It has sometimes two, sometimes four cilia, has no sort of 

 outer membrane, and possesses a great faculty for changing its form. 

 The greater part of the organism is occupied by the chromatophore. 

 It has no pyrenoid. Sperm atozopsis in its vegetative reproduction 

 follows the type of Pi/ratnimonas, and divides longitudinally. Neither 

 the transition to the resting state nor the sexual reproductive process 

 were observed. 



IP Morphology and Physiology of Euglena.* — C. Ternetz writes on 

 the morphology and physiology of Euglena gracilis Klebs. It may 

 occur in four different forms —the normal green form, the hyaline 

 darkness form, the intermediate form, and the hyaline light form. The 

 normal green form can be cultivated purely inorganically, but in that 

 case multiplies very slowly. As regards nitrogen, it prefers compounds 

 of ammonia to nitrates. It flourishes much better in organic culture- 

 fluids, especially when albuminous bodies are present. The number of 

 the chloroplasts is very variable, numbering sometimes more than 

 thirty. The hyaline darkness form represents a local modification of 

 the green Euglena^ and may at any time be restored to the normal 

 form by a return to light. With the exception of the stigma it is 

 wholly colourless. The intermediate form may be regarded as analo- 

 gous to one of the coloured-leaf varieties of the higher plants. It shows 

 different types : sometimes colourless (with the exception of the stigma), 

 sometimes containing vacuoles with red or yellow spots, sometimes 

 tinted lightly with yellow. It arises spontaneously, but only in nutri- 

 tive solutions containing albumen ; it is extraordinarily active, and 

 increases as quickly as the green form. In the course of several weeks 

 it divides into permanently colourless and into normally green indi- 

 viduals. The hyaline light form, which also only occurs in albuminous 

 nutritive solutions, is entirely colourless ; even the eyespot is wanting. 

 It has lost its phototactic irritability, and no longer has the power of 

 forming resting-cysts in albuminous nutritive solutions, but goes to 

 pieces when it stops movement. It shows clearly the stamp of de- 

 generation. It is a constant form. The power of forming chlorophyll 

 is lost. Since neither from chloroplasts nor from leucoplasts are there 

 any products of decomposition, the author designates this the apoplastic 

 form. The formation of the hyaline light form arises either through 

 the intermediate form or direct from the green Euglena. 



West Indian Diatoms.f— E. Oestrup gives an account of the diatoms 

 collected in the Danish West Indies mostly by Dr. F. Borgesen. Of 

 the 145 samples collected 88 are from salt or brackish water, and 57 

 from fresh-water. The former contain 217 species, the latter 73. 

 Twenty new species and one new variety are described and figured. 



* Jahrb. Wiss. Bot., li. (1912) pp. 435-514. 

 + Dansk. Bot. Arkiv, i. (1913) 39 pp. (1 pi.). 



