580 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in which the destruction takes place is not like that in GrapJwsoma, 

 either structurally or developmentally. 



Collenibola from Caves.* — Prof. K. Absolon finds that the Poduridae 

 are well represented in the caves of Moravia. In addition to forms 

 known from other regions, there are certain peculiar cave forms, of 

 which two are described as constituting new genera. In the one — 

 Schafferia emucronata g. et sp. u. — the ocelli are six in number; there is 

 a remarkable postantennal organ, and the springing organs are short and 

 degenerate. The other — Mesachorutes k-ocellatus g. et sp. n. — appears 

 to be intermediate in character between the genera Schotella and Acho- 

 rutes. 



Arctic Collenibola.j — Einar Wahlgren, in the course of a description 

 of the Collembola of the Swedish Expedition of 1899, makes some remarks 

 on the distribution of northern forms. Previously two species only were 

 known from Jan Mayen, but the Swedish collection includes thirteen 

 species, in spite of the brevity of the time at the disposal of the collectors. 

 On the other hand, although there have been many expeditions to Spitz- 

 bergen, only sixteen species have been described from it, and only eight 

 from Beeren Island, in spite of careful search. All the Jan Mayen 

 forms belong to the so-called lower Collembola (Aphoruridae, Poduridae, 

 and Isotomidae), but the author believes that this is largely accounted 

 for by the fact that it is less easy for the higher forms (Smithuridae, 

 Tomocerinae, and Entomobryinae) to cross the polar seas, and is not due 

 to the incapacity of these forms to tolerate low temperatures. Of the 

 thirteen Jan Mayen forms, eight are white in colour, perhaps because 

 the concealed habitat of white forms enables them to withstand the cold 

 more readily. 



New Collembola. J — Prof. Karl Absolon describes as Typldopoclura 

 longicornis g. et sp. n., an interesting cave form found in Herzegovina, 

 and remarkable for its large size, long antennae, and glistening silvery 

 colour. The length of the antennae is due to the great size of the 

 fourth segment, which is larger than all the others put together. 

 Another form from the same district is Verhoeffiella cavicola subgen. 

 et sp. n., which is apparently allied to Heteromurns margaritarius Wkl. 



Structure and Development of Collembola.§ — S. Prowazek has 

 obtained abundant material of Isotoma grisea Lubb., and has been able 

 to make a series of observations on its development. The egg is 

 surrounded by a very resistant coat, the chorion of authors, and is 

 yellowish-green in colour ; polar bodies were not clearly made out. 

 The segmentation is interesting and apparently primitive; it is total 

 and subequal, but later passes into the superficial type. As this change 

 progresses a thin membrane, the cuticula blastodermatica, appears 

 between embryo and chorion, and forms a protective investment. This 

 is to be regarded as an embryonic ecdysis, and is an adaptive peculiarity. 

 The so-called dorsal organ makes its appearance very early, and the 

 author is disposed to regard it as the last remnant of the ordinary 



• 



* Zool. Auzeig, xxiii. (1900) pp. 265-9 (4 figs.). 



t Ofvers. k. Vetensk. Akad. Forhandl., lvii. (1900) pp. 353-75. 



t Zool. Anzeig., xxiii. (1900) pp. 427-31 (2 figs.). 



§ Arbeit. Zool. lust. Wien, xii. (1900) pp. 335-70 (2 pis.). 



