OPALINID CILIATE INFUSORIANS — METCALF 627 



identical on the members of each chromosome pair; (c) the chromo- 

 some segment on which the nucleohis is located may undergo con- 

 siderable structural modification; (d) the behavior of the nucleolus- 

 boaring chromosomes durmg mitosis is the same as that of the other 

 chromosomes; (e) when two nucleoU are close together they may 

 fuse, thus giving rise to apparent variation in the number of nucleoH 

 within the species which has been so often reported by other investi- 

 gators; (J) in the resting nucleus the nucleoH are arranged at random 

 and are located at the periphery; these nucleoH were mistaken for 

 chromosomes by many previous investigators; (4) that the so-called 

 "macrochromosomes" in the opalinids are not chromosomes but 

 nucleolar regions of certain chromosomes; (5) that the so-called 

 "mid-mitotic resting stages" in the opalinids as described by other 

 investigators are misinterpretations. (Nucleoli in the resting nucleus 

 were considered as cliromosomes, while the chromatin reticulum 

 was overlooked by them.) 



Chen, 1937, described a new method for preserving and shipping 

 smears of opalinids. 



Carini, 1937, described seven new species of opalinids found in 

 Brazil: Opalina faber in Hyla faber; 0. elongata in Hyla faber; 0. 

 nebulosa in Hyla nebulosa; 0. rugosa in Hyla nebulosa; 0. rubra in 

 Hyla rubra; 0. raddiana in Hyla raddiana; and 0. mogyana in Hyla 

 leucophyllata. [The descriptions of some of these species are too 

 scant to allow specific identification.] 



Homing, 1937, reported some experimental studies on the cyto- 

 plasmic inclusions of opalinids. In addition to the Golgi bodies that 

 Richardson and Homing (1931) described, Homing distinguishes two 

 principal cytoplasmic components: the mitochondria and the vegeta- 

 tive granules of the endoplasm. The mitochondria react to experi- 

 mental conditions such as alterations in the pH of the external me- 

 dium and cellular injury. Under the influence of radium radiations 

 the mjtochondria are re-oriented so that they assume a transverse 

 polarity to the longitudinal axis of the organism. Later the mito- 

 chondria are segregated by the radiations so that they lie apart from 

 the vegetative granules with which they are closely associated in the 

 normal organism. 



Lavier, 1937, reported the absorption of bile pigments by the 

 trophozoites and cysts of opalinids. The bile pigments may be de- 

 posited in the opalinids in the form of brownish-red crystals. 



Sandon, 1938, reported the presence of Zelleriella in South Africa. 

 Z. (africana A) and Z. {africana B) were found in the rectum of two 

 species of Rana from the neighborhood of Capetown. 



Carini, 1938b, revised the genus Zelleriella inhabiting Leptodadylus 

 ocellatus in Brazil. 



