64 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Incertae Sedis. 



Trichoplax adhaerens.* — Dr. T. Garbowski has made a study of 

 this peculiar auimal. Through a cuticle of several layers there project 

 the cilia, which are not continuous with the cytoplasm, but are merely 

 outer processes of the epithelial cells. The ventral epithelium has no 

 digestive power, this being the function of certain cells of the loose 

 body parenchyma. The food is liquid, chiefly organic decomposition 

 products. Other parenchyma cells, fibrous in character, are disposed 

 dorso-ventrally and act as muscles. The so-called muscles of von Graff 

 are artefacts. In the parenchyma there are large spheres, usually de- 

 scribed as fat-bodies, which seem to be intercellular excretory products. 

 The yellowish-brown globules, which have been variously interpreted, 

 are probably symbiotic Algae (Zooxanthella). Two individuals may 

 fuse in conjugation, and this is preparatory (necessarily?) to fission or 

 " architomy." The animal is not a flattened gastrula, nor a Platy- 

 helminth, but it may be one of the various simple types from which 

 higher Metazoa have arisen. 



Rotatoria. 



New Rotifer: Lacinularia striolata.f — Mr. J. Shephard gives a 

 very complete and elaborate account of this interesting new species, 

 which has much resemblance to L. peduncidata, and, like that species, 

 forms spherical colonies anchored to submerged plants by a peduncle 10 

 to 12 mm. long. The colonies may attain a diameter of 5 mm., and the 

 estimated number of rotifers in such a colony, calculated from those 

 counted in a given area of its surface, gave a total of 3681 for the whole 

 sphere. L. striolata has a very long foot, four-fifths the total length, 

 and the corona is not wider than the body ; it differs from L. pedun- 

 culated mainly in these particulars. It has been found in various places 

 in Victoria, often in great profusion. 



New Rotifer: Melicerta fimbriata.J — Messrs. J. Shephard and 

 W. Stickland figure and describe this new species found in the Botanical 

 Gardens of Melbourne. It has much resemblance to M. tubicolaria, 

 but builds its tube of light brown fibres, each possessing a granular 

 structure, arranged so as to radiate somewhat irregularly from a thin 

 gelatinous tube which fits closely to the body. 



Echinoderma. 



Plutei from Unfertilised Eggs.§— Prof. J. Loeb has been led by 

 his experiments to believe that the only reason why the eggs of marine 

 animals do not develope parthenogenetically is that something in the 

 sea-water prevents it, namely the presence or absence of ions of sodium, 

 calcium, potassium, and magnesium. The two former require to be reduced, 

 the two latter to be increased. Experimenting on the eggs of Arbacia, he 



found that the mixture of about 50 per cent. — n MgCl 2 with about 



o 



* Bull. Acad. Sci. Cracovie, 1899, pp. 87-98. See Amer. Nat., xxxiii. (1899) 

 pp. 747-8. f Proc. Roy. Soc. Victoria, xii. (1899) pp. 20-35 (3 pis.). 



X Vict. Naturalist, xvi. (1899) pp. 38-40 (1 pi.). 

 § Amer. Journ. Physiol., iii. (1899) pp. 135-8. 



