84 Prot, 
PROTOZOA. 
reticulate plasma-network. On entering the alimentary canal of the 
Blatta, the pseudo-navicellae emit young Gregarince, which partially 
embed themselves in the protoplasm of the inner ends of the intestinal 
epithelium-cells ; they consist of cells, each slightly larger than a pseudo- 
navicella, and pear-shaped ; the projecting portion is ultimately sepa- 
rated from the embedded part by a septum, and constitutes an abdominal 
segment, containing the nucleus. 
Gregarina •polymorpha, (36) p. 386, copulates in same way as (?. hlat- 
tarum. 
Monocystis magna, (36) p. 402, pi. xxi. figs. 14-18, becomes embedded 
in epithelial cells, like the Polycysiidea, drawing from the cells a continual 
supply of nutriment. Schneider’s observations on the history of the 
pseud o-navicelljB are confirmed. 
Klossia should include the genus Benedenia according to Schneider, 
(40) p. 398. 
Coccidium. A species has been observed by BOtsciili iu the intestine 
of Lithohius, the first recorded case of the occurrence of the genus in an 
Arthropod, (36) p. 405, pi. xxi. figs. 19-24 ; it resembles that described by 
Eimer from the intestine of the Mouse. 
The so-called Psorospermtce of Fish are constituted by Butsciih (37) 
a distinct group, under the name Myxosporidia. This writer regards 
them as distinct both from Gregarinida and Myxomycetes^ but as finding a 
place by the side of the former organisms. They show some interesting 
points of resemblance to Pelomyxa. Those found in the gills were investi- 
gated chiefly from Cyprinoid Fishes : they develop in the connective tissue 
surrounding the cartilages of the gill-plates, and, by expansion during 
growth, burst the capillaries of the latter, causing extravasation ; they 
have a distinct plasmatic envelope containing nuclei and apparently pro- 
duced by the Myxosporidium itself. The protoplasm of the body is 
filled with very small nuclei containing nucleoli ; the spores have a thick 
two-valvod coat; the polar corpuscules diminish in size when the two 
fibres issue from the spores, heuce the capsules appear to bear the same 
relation to the fibres as the thread capsules of Coelenterata, &c., to the 
threads which they contain ; the spores are nucleated. 
The Myxosporidium of the Pike’s bladder is found in abundance on the 
inner surface of the latter during the winter. Structure described : the 
lobose and filiform processes of the body are comparable to pseudopodia, 
for they manifest slow movements ; the ectoplasm is distinctly marked 
off from the endoplasm, and shows lamination-contours within its own 
substance ; the crystals of the endoplasm are enclosed in fatty globules, 
and probably consist of haematoidin. Formation of spores described : their 
test appears to consist of a single piece ; they are developed from globules 
which occur within the parent Myxospiridium ; of these globules, each 
contains several nuclei, viz., up to six, and sometimes more ; the spores 
arise from them by the division into two of one such mass; the six 
nuclei, in the case where there are six, thus become equally distributed 
between the two products, and of the three in each such new spore 
two disappear and the other persists ; the polar corpuscules originate close 
to the point of disappearance of the two nuclei, not from these nuclei. 
