644 C. CLIFFORD DOBELL. 



16. ScHAUDiNN, F. — "Studien iiber kranklieitserregende Protozoen : I. 



Cyclospora caryolytica, Scliaud., der Erreger der perniciosen 

 Euteritis des Maulwurfs," in ' Arb. Kaiserl. Gesuudbeitsamte,' Bd. 

 xviii, 1902, p. 378. 



17. Stolc, a. — "Beobaclitungen und Versuclie iiber die Verdauung und 



Bilduiig der Kohlenhydrate bei einem aniobenartigen Orgauismus, 

 Pelomyxa palustris, Greeff," in ' Zeitschr. f. wiss. Zool.,' Ixviii, 

 1900, p. 625. 



18. Zeller, E. — " Untersuciiung iiber die Fortpflanzung und die Entwick- 



lungderin unserenBatrachiernsclimarotzendenOpa!inen,"in 'Zeitschr. 

 f. wiss. Zool.,' xxix, 1877, p. 352. 



EXPLANATION OF PLATE 38, 



Illustrating Mr. C. Clifford DobelPs paper on '' Pliysiological 

 Degeneration in Opalina." 



[Figs. 7 and 8 are drawn from living specimens, under a 2'5 mm. (apert. 

 1'25) apocliromatic water immersion objective by Zeiss ; compensating ocular 

 12. The remainder are from permanent preparations : fixed sublimate-alcohol 

 (2 : 1). Figs. 1 — 6, 9 and 12 from specimens stained with Heidenhain's iron- 

 ha3matoxylin. Fig. 10, Heidenhain and eosin. Fig. 11, Weigert's iron- 

 hfematoxylin and eosin. Drawn under a 2 mm. (apert. 1"40) apochromatic 

 oil immersion (Zeiss), with compensating ocular 12. 



All figures are drawn in monochrome for sake of uniformity. In all cases 

 the darker masses are chromatin ; the paler masses surrounded by a light area 

 are the eosinophile bodies.] 



Fig. 1. — Atrichous form in which the nucleus has largely broken up into 

 chromidia. The remains of the nucleus are seen near the middle, with a 

 single large cap-like mass of chromatin. Beneath is seen one large eosino- 

 phile body. Note that many of the chromidia arc in the form of hollow 

 spheres — annular in optical section. 



Fig. 2. — Smaller specimen, completely filled with chromidia. 



Fig. 3. — Specimen in which the chromidia are running together to form two 

 new nuclei. Some indication of the formation of a cyst can be seen. 



Fig. 4. — The chromidia have fused to form two new nuclei, which are 

 approaching one another. 



