ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 459 



genera are formed : it contains the genera Euspongia, Hippnspongia, 

 and Gacospongia, whilst tlie genera Phijllospongia, Carteriospongia, and 

 Stelospongia form his subfamily Chaliuopsinfe. 



The author divides the genus Euspongia into seven subgenera, 

 Irregularis, Triplicis, Laxrfthris, Ditela, Begularis, Densalis, Silicifihris. 

 Various species of the genus are described, in some of which a 

 nervous system, derived from mesoderm, is described ; he mentions 

 Marshall's opinion that all organs in sponges are mesodermal ; a list 

 is given of the various kinds of cells found in the mesoderm, and 

 the development of these is suggested to have had the following 

 course ; — amoeboid wandering cells are present, and retain the 

 appearance of the original mesoderm-cells of the blastula : from these 

 ova, sijermatoblasts, and indifferent tissue-cells have been derived, as 

 well as " spongoblasts " and gland-cells of the skin. Neuromuscular 

 elements were developed from the indifferent tissue-cells, which were 

 further differentiated into ganglia and sensitive cells or true muscular 

 cells. A table is given showing the way in which the " vestibule 

 spaces " may be derived from the ancestral gastrfea by a series of 

 foldings of the wall of the sac. 



In an " addendum " * the author suggests that Halisarca Bassan- 

 gustiorum Carter should have its generic name altered to Oscarella, 

 and he throws some doubt on Carter's description of a single large 

 inhalent pore at the opposite pole to the osculum in Teichonella 

 labyrinthica. 



Protozoa. 



Bursaria truncatella.t — Herr A. Brauer describes the structure 

 and mode of encystation of this infusorian. Specimens are best 

 preserved in a 1-2 per cent, solution of osmic acid, treated with 

 picrocarmine, Beale's carmine, and 2 per cent bichromate of potash, 

 and made transparent by being left for a long time in filtered 

 water. 



The author disagrees with Stein as to the position of the anus, 

 which he always saw on the ventral side, and not in the middle of 

 the hinder edge ; no other infusorian is known to have so large or so 

 completely formed a peristome as this species ; it is only connected at 

 its wide orifice with the body-wall, and has walls of its own ; its cavity 

 is apparently, but not really, divided into two halves ; in the left lies 

 the peristomial groove, and in the right the greater part of the ciliated 

 zone with the subjacent bauds or muscular fibres, and the spoon-shaped 

 depression. 



The contractility of the body of the fresh-water Vorticellinae 

 appears to have its scat in the highly refractive, sharply limited 

 fibres which either arise from the base of the body, or in those with 

 non-contractile stalks, or are direct continuations of the stalk-muscle ; 

 these fibres pass at a more or less obtuse angle to the cuticle, and are 

 inserted at the level of the ciliated ring, whence anastomoses pass to 

 the peristome ; the fibres are separated from one another by granular 



* Proc. Linn. Soc. N. S. Wales, x. (188G) p. 475. 

 t Jouaisch. Zeitschr. f, NaturwiHS., xix. (1885) pp. 489-.'Jl9 (1 pi.). 



2 11 2 



