ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 447 



the spicules in Thy one fusus, and a note upon a stage in the scleroblastic 

 development of the plate-and-anchor spicules of Synapta inhcerens. 



Coelentera. 



Rheotrqpism in Hydroids and Bugula.*— P. Hallez has subjected 

 various hydroids for 4-75 days to variable currents of water, with 

 controls in vessels not agitated. He has experimented with species of 

 Obelia, Sertularella, Hydrallmania, Antennularia, etc. The results are 

 not affected by the rates of the current. One of the chief results is an 

 abundant production of hydrorhizae, which, by budding rapidly, form 

 new colonies. In Bagida, too, an exaggerated production of roots is 

 induced. 



Fresh-water Medusa in River Niger.f — E. T. Browne records the 

 occurrence in the river Niger of Limnocnida tanganicw, a fact of some 

 interest in view of the distance of this river from the Great African 

 Lakes. He thinks that with a sea stretching across the Soudan in the 

 Eocene period one can account for the presence of Limnocnida in both 

 these regions. This solution of the problem removes the need to 

 speculate about the Medusae ascending the Niger from the Atlantic and 

 migrating across Africa. 



Limnocodium at Munich.! — E. Boecker reports the occurrence of 

 the fresh- water Medusoid Limnocodium in the Victoria Regia tank in the 

 Botanic Gardens at Munchen. The specimens seemed to be exclusively 

 males. The hollow tentacles did not seem to have their bases imbedded 

 in the jelly, as Giinther stated. Infusoria, algae, amoebae, etc., were 

 observed in the stomach. 



Free-living Variety of Adamsia rondeletii.§ — Jose Rioja y Martin 

 describes some colour varieties of this common sea-anemone, and notes 

 also that it often occurs altogether apart from mollusc-shells and 

 the hermit-crab, namely, on Zostera marina. Linares has named this 

 free-living variety, libera. 



Californian Shore Anemone. || — H. B. Torrey described Bunodactis 

 xanthogrammica, which has a wide range along the entire Pacific coast 

 of North America, and shows considerable variability. It has been 

 described under at least four different specific and five generic names, 

 but the author clears up the synonymy. The characteristic green colour 

 of the species is found only in individuals exposed to the sun ; it is due 

 to a unicellular alga in the endoderm of the column wall, mesenteries 

 and tentacles. Under wharves or in caves the algae, though present, do 

 not develop so luxuriantly, and the polyps are correspondingly pale. 

 The material for the illustrative plate was destroyed in the recent fire in 

 San Francisco, but the plate will be forthcoming later on. 



* Comptes Rendus, cxli. (1905) pp. 840-3. 



t Ann. Mag. Nat. Hist., xcix. (1906) pp. 304-6. 



t Biol. Centralb., xxv. (1905) pp. 605-6. 



§ Boll. R. Soc. Espafi. Hist. Nat., v. (1905) pp. 457-9 (1 pi.). 



|| Univ. California Publications, iii. No. 3 (1906) pp. 41-5 (1 pi.). 



