258 SUMMAEY OF CUEEENT EESEAECHES EELATING TO 



regarded as an orifice by means of wliicli the young escape ; Prof. 

 Vejdovsky offers no opinion on this view, but he says that he thinks 

 it more probable that the polar process is completely closed by the 

 horny membrane ; the air-tubes of dried gemmules of S. fragilis are 

 filled with large air-vesicles, just as in S. carteri. The North 

 American genus Carterius is very interesting in having a high hollow 

 tube which is always directed upwards when the gemmule is thrown 

 into water. In S. fragilis the air-tubes are proportionately larger than 

 in any species known to the author and must contain a large quantity 

 of air. 



Sponges from South Australia.* — Mr. H. J. Carter continues 

 his account of sponges from Port Phillip Heads, South Australia. 

 An extended diagnosis is given of the Axinellida, and a new family 

 Pseudoechinonemida is instituted. Among the Eenieridfe we have 

 the new group Phloeodictyonina ; the excavating sponges form a new 

 family Eccoelonida, and a rearrangement of the Holorhaphidota is 

 tabulated. 



A new group, Suberitina, is formed to contain the former groups 

 Cavernosa, Compacta, Laxa, and Subcompacta. Other new groups 

 are Polymastina, Trachyina, Chondropsina (provisionally), and 

 Stellettinopsina. 



Siliceous Sponge-spicules from the Chalk.f — Herr P. Pocta has 

 a second paper on isolated siliceous sponge-spicules from the chalk- 

 formations of Bohemia. He discusses the modifications of four-rayed 

 forms caused by the shortening of one or more of the rays ; where 

 one is shortened we have, of course, three-rayed forms ; if one ray is 

 at the same time lengthened we get anchors with a dichotomous head ; 

 sometimes the persistent rays bifurcate. There are notes on quinque- 

 radiate and sexradiate spicules, the former of which are wanting from 

 his collections, while the latter are rather rare. The multiradiate or 

 stellate spicules have not been observed by him, but nearly all the 

 spicular spherules described by Zittel have been found in the 

 Bohemian formations. The paper concludes with a list of species, 

 four of which are new. 



Sponge-Spicules from the Horn-stone of Briisan.J — The same 

 author gives an account of ten species from the horn-stone of Briisan, 

 of which, in one case only {Ligidium carteri Hinde) was he able to 

 distinguish the species. 



Protozoa. 



Nuclear Division in Protozoa. § — Dr. W. Pfitzner, after many 

 unsuccessful attempts to perfectly colour the chromatic constituents 

 of the nucleus, and at the same time to clear up all the other parts of 

 O^alina ranarum, made use of the following method. He cut short 



* Ann. and Mag. Nat. Hist., xvi. (1885) pp. 347-68, and xvii. (1886) pp. 40-53, 

 112-27. 



t SB. K. Bohm. Gesell. Wiss. Prag, 1884 (1885) pp. 3-14 (1 pL). 



X Tom. cit., pp. 243-54 (2 pis.). 



§ Morphol. Jahrb,, xi. (1885) pp. 454-67 (1 pL). 



