Species 



I. In the process of division the 

 nucleus divides repeatedly, 

 and a number of the nuclei { 

 thus formed pnss into each of 

 the resulting spheroids. 



B 



42 NOTES AND MEMORANDA. 



Contributions to our knowledge of the Protozoa. — Professor A. 

 Sclineider has a short but important pajjer (with a plate) on this 

 subject, in the ' Zeitschrift f. wiss. Zool.,' * in which he describes his 

 recent observations on Actinosjjhcerium, Miliola, Trichosphcerium (a 

 new genus), and Chlamydomonas. 



Acthiosplicerium Eichornii. — Schneider's comparison of his own 

 researches with those of Brandt, Greeff, and F. E. Schulze, lead him to 

 think that this species really includes four distinct species, agreeing 

 with one anotVier in the vegetative condition, and differing only in the 

 reproductive stage. The observations on which this opinion is based 

 are shown in the following table compiled from Schneider's paper. 



f 1. After the completion of the process "j 

 of division, each of the two sphe- 

 roids Climes 1o lie in a special 

 cyst, or rather in a special com- 1 "^'T 

 partmont of the common cyst : t 

 the spheroids do not subse- 

 quently unite, and their siliceous 

 case is single (Schneider). 

 After division the two spheroids' 

 do not, or not always, lie in 

 special cavities in the cyst : after 

 the process of division the two 

 spheroids unite again : their sili- 

 ceous case is double (GreeiT). 



II. In the process of division / ^ ^^f^^^. ^^^^^^^^ ^i^e spheroids con- \ ^ 



the nucleus disappears, new -^^^ (Brandt). / ^ 



nuclei afterwards appearing, J ^_ j^.^^,.,^^ ^^ ^j^^ spheroids) 



one of which passes into each \ ^^^^^ ^^^ ^^^^^ ,^^ (Schneider, D 



spheroid : the siliceous cases ^ ^ Schulze). 

 are thinner than in (i.). \ 



A further evidence of the distinctness of this form is afforded by 

 the difference in their habits : of the two observed by Schneider, the 

 species A, from the canal in the Berlin Zoological Gardens, fed chiefly 

 on Cijdops, to which it clung by its pseudopodia, allowing itself to be 

 carried about by its prey until the latter was killed : the species D, 

 from ditches at Giessen, never devoured Gyclopidaj, but fed chiefly on 

 Chlamydomonas, and amongst higher animals confined itself to the 

 smaller Kotatoria, 



2, Development of Miliola. — In a species of this genus observed at 

 Fohr, distinct nuclei were observed. Multiplication took place by the 

 protoplasm being divided into nucleated masses, of which there were 

 finally seen to be two kinds ; small naked cells, probably representing 

 spermatozoa, and large oval cells provided with a distinct membrane, 

 and seeming to represent ova. No stage was found between these 

 latter, and ''germ masses, consisting of a very distinct cell-wall 

 enclosing contents half protoplasmic, half fat like. The fatty body 

 disappeared, and the germ was converted into a young Miliola, with a 

 single, globular, thin-walled chamber, provided with one large aperture 

 ancf several small ones, through which pseudopodia were- protruded : 

 no nucleus was visible in this stage. The tubular portion of the shell 

 was seen to begin as a hand-shaped process near the mouth. The 

 young Miliolce continued to grow through the winter, and then the 

 * ' Zeit.sch. f. wiss. Zool.; vol. xxx. (Suppl.), p. 446. 



