400 SUMMARY OF CURRENT RESEARCHES RELATING TO 



condition, their contents sometimes segmenting into cysts. (2) By entire 

 cell-rejuvenescence, similar to that described by Schiitt in Peridinium ; 

 the contents escape in the form of two swarm-spores, the further history 

 of which is not followed out. (3) By fission, corresponding to division 

 in the motile state. 



Development of Actinosphserium eichhorni.* — Mr. J. M. Stedman 

 remarks that the youngest examples of this species seen by him re- 

 sembled white blood-corpuscles with a distinct and sharply defined 

 nucleus. Later, a vacuole appears, which attains to a very large size, 

 and at this stage a pseudopodium may be present. Two of these were 

 seen to unite, and in the course of five minutes the two vacuoled forms 

 developed a ray, and the characteristic axis-thread could be seen in its 

 interior. The number of rays in younsf forms is of no special value, as 

 it varies with different individuals of the same age. The form under 

 observation was, a little later, seen to unite with one which had three 

 vacuoles but no rays, and immediately afterwards a spherical form was 

 assumed. Again a union occurred, and now the characteristics of 

 A. eichhorni began to be apparent. The author suggests that in the 

 autumn, at any rate, full-grown Heliozoa become encysted, that the 

 protoplasm divides and subdivides until it is converted into a mass of 

 minute bodies, which, when the cyst is ruptured, make their escape 

 into the surrounding water, and then appear as naked spherical masses 

 of granular protoplasm with a nucleus. 



New Type of Astrorhizidse.t — Mr. H. B. Brady gives an account of 

 an undescribed type of Khizopod, dredged by Mr. Wood-Mason in the 

 Bay of Bengal. Masonella is proposed for the generic name, and two 

 species, M. planulata and M. patelliformis, are recognized. The general 

 structural features can almost be read by the naked eye, a,nd are easily 

 made out under a low magnifying power. There is a central chamber 

 with a number of radiating tubes which extend, either simple or 

 branched, to the periphery. We have here branched and radiate 

 Astrorhizpe with the sandy investment continued between the arms, so 

 as to produce an even, rounded, peripheral outline. The species appear 

 to be common at the localities in which they were found. 



New Gregarines.J — Prof. J. Leidy describes a new species of 

 Gregarina, which he proposes to call G. philica, found in the proventriculus 

 of a common American beetle Nyctohates pennsylvanicus. It is remark- 

 able and apparently peculiar in its mode of conjugation, for the pairs 

 conjoin with the heads together and the bodies side by side. G. actinotus 

 sp. n. is frequent in the common Myriopod Scolopocryptops sexspinosus ; 

 it looks like a minute Echinorhynchus when found adherent by its 

 rostrum to the inner surface of the proventriculus. G. megacephala is a 

 new species found in Cermatia forceps which appears to be allied to 

 Dufouria agilis found in the larva of a Hydracantliaris. Another new 

 species is called G. microcephala ; it was found in the tenebrionid beetle 

 Hoplocepliala bicornis, and bears a close resemblance to EcMnocephalus 

 Mspidus of Schneider, but is without the digitiform processes to the 

 head. 



* The Microscope, viii. (1888) pp. 333-61 (1 pi.). 

 t Ann. and Mag. Nat. Hist., iii. (1889) pp. 293-6. 

 X Proc. Acad. Kat. Sci. Philad., 1889, pp. 9-11. 



