ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 617 



North American Scyphomedusse. * — C. W. Hargitt contributes a 

 useful synopsis of the Stauromedusae (3 genera), Peromeclusa? (1 genus), 

 Cubomedusse (1 genus), and Disco rnedusaj (12 genera) of North American 

 waters. 



Prophysema hseckelii.f — N. Leon describes this Gastrread, which 

 resembles HaUphysema tumanowiczii described by Bowerbank as a 

 sponge, and referred by Haeckel to the Gastrasadse under the title 

 Prophysema. Leon's form, obtained from the island of Radoe, north 

 of Bergen, is a club-shaped body, 2 mm. in length by -| mm. in thick- 

 ness ; the oral surface is free with a circular opening ; the aboral end 

 is fixed by a short, solid stalk, whose base is a plano-convex disc ; the 

 wall of the body is thick and without pores ; the ectoderm is a syncytium 

 with various kinds of sponge-spicules and sand-grains fixed on to it ; 

 the endoderm shows flagellate cells. The author scouts the idea that 

 Haeckel could have called a Foraminif er a Gastrasad, as Delage and others 

 have suggested. That Prophysema haeckelii sp. n. is not a Foraminifer 

 is certain. 



Porifera. 



Carterius Stepanowi Dyb.J — 0. Zacharias notes that this fresh- 

 water sponge of Bohemia, Galicia, Hungary, and Russia, has been re- 

 ported from Mehlingen in the Rheinpfalz by R. Lauterborn, and that 

 it seems also to occur in the Schohsee at Plon. Not that Zacharias 

 found the sponge, but he got in the bottom mud numerous flesh-spicules 

 exactly corresponding to those figured by Lauterborn. Zacharias also 

 calls attention to the fact that while all other fresh-water sponges have 

 species of Zoochlorella as symbions, Carterius stepanowi Dyb. is said by 

 Lauterborn to contain Scenedesmus quadricauda, one of the Palmel- 

 laceas. 



Protozoa. 



Influence of Light on Amoebse and their Cysts. § — Georges Dreyer 

 has experimented with light passing through rock-crystal, through un- 

 coloured glass, and through blue glass. The results show that the cysts 

 are much more resistant to the destrnctive influence of the rays of light 

 than the unencysted amoeba? are, 30-33 times more in the case of the 

 rock-crystal, 5 ■ 5-6 times more in the case of uncoloured glass, five times 

 more in the case of blue glass. Cysts are destroyed in about 25 minutes 

 by light passing through rock-crystal, in 60-70 minutes when the same 

 quantity passes through uncoloured glass, and in 70-80 minutes in the 

 case of blue glass. Light passing through rock-crystal (ultra-violet 

 rays) kills the amoeba? 13-14 times quicker than when it passes through 

 uncoloured glass, and 18-20 times quicker than when it passes through 

 blue glass ; but in the case of the cysts the fatal effect is reached 

 2 • 5-3 times more quickly with rock-crystal than with uncoloured glass, 

 and three times more quickly than with blue glass. 



* Araer. Nat., xxxvii. (1903) pp. 331-46 (6 figs.). 

 t Zool. Anzeig., xxvi. (1903) pp. 41S-9. 

 % Biol. Centralbl., xxiii. (1903) pp. 483-4. 



§ Oversigt k. Danske Videnskab. Selskabs Forkandl., 1903, No. 3, pp. 399-421 

 (2 pis.). 



