380 SUMMARY OF CURRENT RESEARCHES RELATING TO 



with a lens, tliey were observed to be covered with delicate rays. On 

 transferring some of the bodies to the field of the Microscope, they 

 proved to be giant specimens of the larger sun-animalcule, Actino- 

 sphceriiim Eiclihornii. They measured from three-fourths to one milli- 

 metre in diameter, indei^endent of the rays, which extended from one- 

 fourth to half a millimetre more. One of the smaller individuals 

 cjntained four water-fleas [Daplmia), a third of a millimetre long ; and 

 one of the larger contained six of these. The Adiuosphcerium appears 

 to be tenacious of life, several siiecimens having been retained alive and 

 in good condition for three days in a drop of water in an animalcule 

 cage. They had discharged the Daphnia, but retained their original 

 size. One of oval form measured 1 mm. long by 0'75 mm. broad. 

 The smaller ones measured • 75 mm. in diameter. After another 

 day they ajii^eared in good condition ; but the rays were contracted 

 so as to be about half the original length, and many had a minute 

 granular ball at the end, apparently effete matter thrown off from 

 them. At this time the animalcules were returned to the aquarium. 



Dimorphism of Foraminifera.* — MM. Meunier-Chalmas and 

 Schlumberger, attracted by the discovery by one of them of the pre- 

 sence of two forms in every species of Nummulite, have lately directed 

 their attention to the Miliolid^e, where they have observed similar 

 phenomena ; so that dimorphism is to be detected in both the great 

 divisions of the Foraminifera-Perforata and Imperforata. The di- 

 morphism of the Foraminifera is characterized by a difference in the 

 size and arrangement of the primary chambers ; the smallest and 

 those of a median size have a central chamber, which is relatively 

 very large (Form A), while in larger forms this cavity is only visible 

 when highly magnified (Form B). In a given species no external 

 character, save that of size, would give the least suspicion of this 

 difference. 



The authors proceed to give some details of the distinctive cha- 

 racters of the two forms, and promise in a further communication to 

 discuss the hypotheses by which this remarkable difference may be 

 explained. 



Vampyrella Helioproteus, a New Moneron.j — T. W. Engelmann 

 describes this new organism, which he found among Confervce in the 

 neighbourhood of Utrecht. It is distinguished from all previously 

 known forms by the " hcliozoa-form " (globular, with long pseudo- 

 podia), being able to pass over into the round flat discoid amoeba- 

 form. This metamorphosis was observed in three instances, and 

 extended over about five minutes. In the heliozoa-form the organism 

 moves by means of its long contractile pseudopodia, like an Adino- 

 sphcerium ; in the amoeba-form it creejis without pseudopodia or change 

 of form. It bears a very close resemblance to Hijalodiscus ruhicundus 

 (Hertw. and Less.), differing only in the absence of a nucleus and of 



* Comptes Renchis, xcvi. (1883) pp. 862-6. 



t K. Akad. van Wetensch. Amstcrtluin, Nov. 25, 1882. See Bot. Centralbl., 

 xiii. (1883) p. 211. 



