ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 295 



Nuclear Division of Amoebidiiim parasiticum.* — II. Raabe has 

 studied the nucleus of this parasite which occurs often on the appendages 

 of Daphnids and other fresh-water Crustacea. The nucleus is vesicular, 

 without a membrane, with a distinct karyosome. There is a reirular 

 reticulum of achromatin in the peripheral re<i:ion and several chromatin 

 elements on the threads and intersections. The centriole divides first, 

 then the karyosome. Sometimes the karyosome, instead of dividing 

 equally, gives off a bud about a third of itself in size. Sometimes there 

 is a multiple nuclear division. Besides this amitotic division, there is h 

 true mit(^sis, showing six to eight chromosomes. The centriole directs 

 the process. It divides into two, which move to the poles of the mito- 

 sis. There is a centrodesmosis during all the stages of the division. 

 There is no spindle nor cytoplasmic aster. 



Structure and Relationship of G-onyaulax palustris.f — C. A. 

 Kof oid and J. R. Michener point out that Gonyaulax palustris Lemmer- 

 mann requires a new genus, for which the name Di/iosjjhsera is proposed. 

 The skeleton consists of an apical series of plates, six precingulars, six 

 girdle plates, five postcingulars, and one antapical. It is related to 

 Gonyaulax by certain skeletal characters, such as the six precingulars, 

 six girdle plates, and one antapical. In the presence of but a single 

 antapical it resembles also Amphidinium, FerkUniella, and Spiraulax. 

 The reduction of the postcingulars from six to five plates, and the 

 obliteration of the posterior intercalary, might well be consequent upon 

 skeletal concentration attendant upon the spheroidal form and the 

 slightly smaller size of the hypotheca as compared with the epitheca. 

 A compensating expansion of the ventral area is also evident. 



Haeckel's Sethocephalus eucecryphalus.J— C. A. Kofoid points out 

 that this organism referred by Haeckel to the Radiolaria is the Tintinnid 

 infusorian, which Brandt described as Gyttarocylts cassis Haeckel var. 

 pJagiostoma. 



Mitochondria of Hsemogregarina sergentium.§ — G. Viguier and 

 A. AYeber have studied the numerous mitochondria in different stages of 

 this Haemogregarine — very fine granules which occur diffusely or in 

 groups, some elongating in division, some massed at one end, others 

 grouped near the nucleus. Besides mitochondria there are small 

 granular masses which stain like the nucleus, and are regarded as extra- 

 nuclear chromatin, as chromidia in fact. In the more advanced stages 

 of development the mitochondria are much less abundant, and occur 

 without apparent order. 



Barrouxia schneideri.|| — C. Schellack and E. Reichenow discuss the 

 coccidia found in the intestine of Lithobms, namely Adelea ovata, 

 Etmeria lacazei, E. schuhergi, and Barrouxia Schneider i. They describe 

 the hfe-history of the last-named — the merozoites, the schizonts, the 

 nuclear divisions, the formation of raacrogametes and their maturation, 

 the formation of microgametes and the fertilization, and the sporogony. 



* Arch. Zool. Exper., x. (1912) pp. 371-98 (1 pi.). 



+ Univ. California Publications (Zool.) xi. (1912) pp. 21-8 (8 figs.), 



; Univ. California Publications (Zool.) ix. (1912) pp. 353-7. 



^ C.R. Soc. Biol. Paris, Ixxiv. (1913) pp. 664-6. 



n Arb. k. Gesundh., xliv. (1913) pp. 30-77 (3 pis.). 



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