ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 259 



V. Eoboz. It occurs fixed on algee in masses of very variable size, 

 form, and arrangement, occurring in monotlialamous, ditlialamous, 

 trithalaraous (with the broad third chamber communicating externally 

 by two adjacent apertures), and polythalamous forms. Six chambers 

 was the maximum ever observed. The thin, porcellanous, calcareous 

 shell is so transparent as to let the brick-red granular protoplasm be 

 seen beneath. There are numerous pores, and the mouth is always 

 at the free end of the chamber. The protoplasm does not fill the 

 shell, but sends off delicate hyaline threads to the shell- wall. The 

 anastomosing pseudopodia serve exclusively for getting food. Nume- 

 rous round nuclei were observed in polythalamous forms, but only 

 one in monothalamous forms (cf. Hertwig's observation on young 

 Miliolidfe). The classificatory position of Calcituha is among the 

 MiliolidaSj of which family it is a primitive example not yet definite 

 in form. 



Archerina Boltoni.* — E. Eay Lankester gives an account of a 

 new genus of Protozoa, allied to Vampyrella, and remarkable for 

 being chlorophyllogenous ; it was discovered by Mr. T. Bolton in 

 ponds in the neighbourhood of Birmingham, associated with desmids 

 and other minute chlorophyll-bearing alg£e. 



The first growth-phase observed is the Actinophryd-form, in which 

 there is a spherical body 1/2000 in. in diameter, consisting of a 

 sharply outlined mass of refringent protoplasm, from which radiate 

 a number of very delicate but stiff filaments ; these are motionless. 

 Within the body is a large spherical vacuole, and sometimes the 

 whole appears of a bright green colour ; when, however, the organism 

 is caused to roll over the green colour is seen to be limited to two 

 masses — a bifid, or in other cases a single chlorophyll-corpuscle; 

 this takes the place of a nucleus, and round it there centre the life 

 and growth of Archerina ; its division precedes and is invariably 

 followed, sooner or later, by that of the protoplasm of the whole 

 organism. There is no evidence at all that this is a cell-nucleus ; no 

 chromatin-substance is to be observed at the time of division, and the 

 process usually results in the formation of four and not of two 

 daughter-bodies. 



The author discusses the parasitic nature of chlorophyll-corpuscles 

 in Hydra, and urges that the " tetra-schistic corpuscles " of both 

 Archerina and H. viridis do not resemble any known unicellular green 

 alga, and that there is no reason " for attributing to them a fanciful 

 origin and history differing essentially from that of other coloured 

 corpuscles and such products of the modification of cell-substance." 



Stages of encystation and of vegetative growth are next described ; 

 and we have then an interesting account of a very curious character- 

 istic. " Groups of ghost-like outlines corresponding to chlorophyll- 

 corpuscles and their radiant filamentous pseudopodia, entirely devoid 

 of any substance," were observed; these are regarded as being un- 

 doubtedly skeletal products of the solid protoplasm which has with- 

 drawn from them ; they may be compared to the numerous cellulose 



* Quart. Jouin. Micr. Sci., xxv. (1885) pp. 61-74 (1 pi.). 



S 2 



