ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 519 



Porifera. 



Australian Aplysinidse.* — Under the title of Coelenterates of 

 the Southern Seas II., E. von Lendenfeld gives an account of some 

 new sponges. 



Of these the first is Aplysilla violacea, the general appearance 

 of which is first described ; an examination of the skeletal structures 

 shows that there are some striking differences between the Adriatic 

 and the Australian species as to their modes of branching. The 

 pores of this species are never closed, though there is a sphincter- 

 like arrangement of contractile fibres by means of which the size of 

 their aperture can be diminished. The histological structure is then 

 carefully described, and in an account of the mode of digestion it is 

 stated that if these sponges are placed for some days in water in 

 which fine particles of carmine are suspended, it will be found that 

 the epithelial cells not only of the afferent canals, but also of the 

 ciliated chambers, take up these particles, and that they are also 

 found, although in less quantity, in the epithelium of the efferent 

 canal system of the oscular tube and of the outer surface. In other 

 words, all the free surfaces are able to take up foreign bodies ; and 

 the same is true also of the migratory amoeboid cells. If we remove 

 the sponge from the carmine-containing water, and place it in fresh 

 sea- water, we may follow out the fate of the carmine granules. After 

 about six hours the epithelial flat-cells of the upper wall of the sub- 

 dermal space, and the collar cells of the ciliated chambers are free 

 from carmine, and particles of this substance will be found in the 

 water ; on the other hand, the amoeboid cells underlying the epithelium 

 of the subdermal space will be now seen to contain carmine, although 

 before they had none at all. These observations lead to the con- 

 clusion that, in A. violacea, small organic bodies are taken up from 

 the ectodermal flattened cells of the subdermal epithelium, and make 

 their way into the subjacent amoeboid cells. Here the injected matter 

 is digested, while the amoeboid cells migrate, carry the undigested 

 remains to the ciliated chambers, and then pass them on to the 

 collared cells, whence they are extruded. Infusoria may frequently 

 be observed in the subdermal spaces and in the afferent canals, while 

 diatom-valves may sometimes be seen in the migratory cells. The 

 presence of glandular cells is also noted, and they are said to closely 

 agree in structure with the spongoblasts. Although this sponge is 

 hermaphrodite, self-fertilization is guarded against by the earlier (by 

 about fourteen days) maturity of the male elements. 



After an account of the characters of the generative products and 

 of the horny fibres, Lendenfeld passes to Dendrilla, a new genus, 

 distinguished by the facts that the mesodermal connective tissue 

 contains no granules and is hyaline, as in Aplysilla; the ciliated 

 chambers are large, saccular, and arranged radially; the sexes are 

 united, and the genital products are arranged in irregularly-sbapcd 

 groups ; large subdermal spaces are not only developed under the 



* Zeitschr. f. Wiss. Zool., xxxviii. (1883) pp. 234-313 (4 pis.). 



