C6 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



V. pusilla, V. mollis, V. aqua [e] dulcis, and V. platysoma. Opercularia 

 allensi is about twice as large as 0. nutans, while the height of its colony- 

 is much less ; 0. vestita is also described. Thuricolopsis differs from 

 Thuricola in that the loricso have an internal, narrow, flexible, valve- 

 rest, aud the zooid is attacbed posteriorly to the lorica by a distinctly 

 developed pedicle. In this genus are placed Thuricola innixa Stokes, 

 and T. hellicottiana sp. n. Platycola coelochila and Lagenoplirys patina 

 are next described. Histrio erethisticus is very difficult to study owing 

 to the animalcule haviug " a most annoying habit of suddenly darting 

 backward for a distance seldom exceeding its own lengtb." Descrip- 

 tions of Solenophrya odontophora, Acineta bifaria, A. macrocaulis, and 

 A. acuminata complete the paper. 



Relationships of Foraminifera.* — Herr M. Neumayr divides 

 shelled Foraminifera into three phylogenetic grades ; (a) the quite 

 irregular and primitive Astrorhizidae ; (b) the series with merely 

 agglutinated shells ; (c) the compactly shelled forms which he believes 

 to have arisen from tbe former. His classification is thus summarized 

 (in compressed form). 



Irregular 

 agglutinated 

 grade. 



Astrorhizidse. 



Karyokinesis of Euglypha.f — Herr W. Schewiakoff has made a 

 careful study of the phenomena of division in Euglypha alveolata. 

 Division is prefaced by the protrusion of cell-protoplasm and of shell 

 plates from the mouth of the shell. The protrusion as it grows is clad 

 with a new shell, over which for a time the alveolar and granular proto- 

 plasm flows. The internal changes begin in the protoplasm of the 

 hyaline zone, which increases in volume, and differentiates into two 

 layers — an outer, denser and reticulate stratum, and an inner clear 

 region round the nucleus. 



(1) The nucleus is homogeneous, and not rich in chromatin. 

 (2) The " cyto-chylema " of the clear region penetrates the persistent 

 nuclear membrane, and conditions the increase of the nucleus, which 

 acquires a reticulate structure and more chromatin. The nucleo- 

 hyaloplasm and the fine granules accumulate at the nodes of the net- 



* SB. Akad. Wiss. Wien, xcv. (1887) pp. 156-86. 

 t Morph. Jahrb., xiii. (1887) pp. 193-258 (2 pis.). 



