190 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Porifera. 



Modifications or Metampy in Halichondria panicea and in Sube- 

 rites domuncula. * — George Bidder contrasts the deep-water H. panicea 

 of Exmouth with the surf specimens from Plymouth, and the dense 

 S. domuncula from the back of a hermit-crab with looser (ripe plum- 

 like) specimens found growing on rock in the deep waters of Millbay 

 Channel. The differences are referable to the differences in the con- 

 ditions of life ; they are not due to germinal variations. It appears 

 useful, in instances where this can be proved, to have a term for 

 such observed difference, and Mr. Bidder suggests " metamp " (from 

 fjuerafjure-^oixai = " to put on a different dress "). But would not the 

 technical use of the word " modification," or the term " somatic modifi- 

 cation " suffice ? The author believes that not only varieties, but many 

 so-called species of sponges, are merely " metamps " of each other. 



Sycon compressum.f — George Bidder asks whether the unique 

 dermal spicules of this sponge are adaptive to peculiar circumstances in 

 its mode of life. Though apparently fragile, it is a sponge with great 

 endurance, able to resist evaporation and the entrance of noxious fluids. 

 While S. compressum and S. ciliatum live side by side in every sheltered 

 cranny, on the working tops of the rocks S. compressum is alone — often 

 with little even of seaweed hardy enough to bear it company — exposed 

 for hours every day to sun, rain, or wind. The thick, continuous cortex, 

 set with its dense mass of club-shaped radial spicules, enables the 

 sponge to pursue its daring existence, clothing it with a deep armour of 

 calcareous mosaic, through which, when the skin is contracted on its 

 pores, a minimum amount of permeation and evaporation can take place. 

 The shillelagh-like outer ends of the spicules serve, like the heads of 

 iron nails set in a pile at sea, to cover and protect the surface of the 

 substance in which their points are embedded. The flat form, whose 

 sides come gradually together if evaporation occurs, is also adaptive. 

 No bubble is ever formed in the cloaca. Thus " the most definitely 

 characterised common species of sponge has the most definite use for 

 its species characters." 



Sponges from New South Wales.J — Thomas Whitelegge describes 

 a collection of six hundred and thirty sponges from the coast of New 

 South Wales. In naming the sponges from the type-collection in the 

 Australian Museum, he found that the descriptions in Dr. B. von 

 Lendenfeld's ' Descriptive Catalogue of the Sponges in the Australian 

 Museum ' do not agree in many cases with the characters of the type 

 specimens, and he therefore regards the Catalogue as unreliable for the 

 determination of species, and rejects many of von Lendenfeld's names. 

 About eight species and varieties of the sponges in the collection prove 



to be of economic value. 



Protozoa. 



" Artificial Protoplasm." § — H. S. Jennings gives a very interesting 

 account of a series of experiments desigued to illustrate the protoplasmic 



* Journ. Mar. Biol. Ass., vi. (1902) pp. 380-2. f Tom. cit., pp. 376-80. 



J Records of Australian Museum, Sydney, iv. (1901) pp. 55-118 (15 pis.). 

 § Journ. of Applied Microscopy and Laboratory Methods, Rochester, N.Y., v. 

 (1901) pp. 1597-1602. , 



