284 SUMMARY OF CUERENT RESEARCHES RELATING TO • 



agilis, which feeds on the iatex of the spurge, especially Euphorhia 

 helioscopica. In the food-canal there is longitudinal division of the 

 Leptomonas and isogamous conjugation. Curious giant forms occur, 

 but their meaning is obscure. Very minute forms pass from the 

 mesenteron into the salivary glands, where they form big masses. 

 Encysted forms also occur in the rectum and the faeces. The Hemip- 

 teron is the primitive host and the life-history may be complete. 

 Several different forms, besides the narrow elongated type, occur in the 

 latex and fruit of the infected spurge. J. A. T. 



Movements of Vorticella. — Faure-Fremiet (Cotnptes Rendus Soc. 

 Biol., 1920, 83, 1382). The myoneme is extremely long in proportion 

 to its diameter ; the thickening on contraction is minimal. The stalk 

 cannot be compared to a flagellum, though in the planktonic Vorticella 

 mayeri it functions like a giant flagellum. In electrical excitability the 

 stalk corresponds to that of rapid muscles in Invertebrates. The 

 coiling of the stalk differs in different species and depends on the 

 structure of the elastic sheath and the unequal contraction of the 

 myoneme. The muscular filament is a differentiation of the central 

 cord, which corresponds to the terminal portion of the body of the 

 Infusorian. J. A. T, 



New Flagellates. — W. Conrad (Recueil Inst. Bot. Errera, 1920, 

 10, 65-79, 2 pis.). Description of the structure and life-history of two 

 new Chrysomonads. In 3Iallomonas mirahilis sp. n. there are amoeboid 

 and palmellar stages. The cell leaves its siliceous carapace and 

 becomes a very active amoeboid form, giving off short pseudopodia. It 

 lives holophytically and by engulfing. In a few cases there are very fine 

 pseudopodia. The amoeboid stages come to rest, round themselves off, 

 form a peripheral gelatinous layer, and pass into the palmella phase. 

 Chrysomonads multiply by longitudinal division and by forming zoo- 

 spores ; in Mallomonas mirahilis Conrad observed longitudinal division, 

 but no formation of free-swimming spores was observed. Endogenously- 

 formed resting spores occur. A description is also given of 31. calva 

 Massart, in which the carapace, instead of consisting of imbricated 

 scales, shows transverse rings bearing extremely short needles. 



J. A. T. 



Fresh-water Anaerobic Ciliate. — Chancey Juday (Biol. Bulletin, 

 1919, 36, 92-5). In many Wisconsin lakes more or less of the bottom 

 stratum (hypolimnion) and the muddy ooze at the bottom show no free 

 oxygen for a certain time (three to four weeks to three to four months) 

 during the summer stagnation period. AYhen the minimum is reached 

 for plankton Crustaceans they rise to a higher level where oxygen is 

 more abundant, and so do some insect larvte. But many remain, and a 

 Ciliate (Hke a species of Enchel/js) has been studied as illustrating true 

 anaerobic life. It disappeared promptly when the water became well 

 aerated. A definite correlation was proved between the occarrence of 

 the Ciliate and the lack .of dissolved oxygen. The stratum occupied 

 had at most a minimal amount of oxygen, and most frequently none 

 at all. J. A. T. 



