ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 567 



Study of Triconymphidse.* — Carlos Franga contributes some obser- 

 vations on these curious Protozoa. He deals first with Trkonymplia 

 agilis, found by Leidy in 1877 in Termes flavijjes in North America. It 

 also occurs in Leucotermes lucifugus in Italy and Portugal. In the same 

 insect there is another type, Leidya metchnikovi g. et sp. n., which Leidy 

 regarded as a young form of Tricomjmpha agilis. It has an elongated 

 shape, with a delicate anterior end. There are flagella over the whole 

 surface in a double spiral. At the anterior end there is an elongated 

 siderophilous structure, on which small filaments are inserted like the 

 barbs of a feather. These bear the anterior flagella. The siderophilous 

 structure bifurcates posteriorily, and forms a double basis for the innu- 

 merable flagella covering the surface. There is a single relatively large 

 nucleus w'ith very compact chromatin. Fran9a recognizes the order 

 Hypermastigina of Grassi and Foa, and four families — CalonymphidiB 

 Grassi, LophomonadidjB Grassi, Triconymphidaj Leidy, and Holo- 

 mastigidfe fam. n. (including Pseudotriconympha, Holomastigotoides, and 

 Leidya). 



Giardia from Meadow-mouse. f — C. A. Kofoid and E. B. Christiansen 

 describe Giardia microti sp. n., from the intestine of Microtus californicus. 

 The new species differs in appearance, proportions, and stainability from 

 the widely-prevalent Giardia muris. Abundant material was secured in 

 various stages of binary and multiple fission and in encystment, including 

 the so-called " copulation cysts," and cysts in w'hicb multiple fission had 

 produced a 16-nucleate plasmodium or somatella. The organism (a 

 binucleate somatella) shows the extranuclear organellte known in other 

 species. The neuromotor apparatus consists of a rhizoplast passing from 

 the karyosome through the centrosome at the anterior pole of the nucleus, 

 thence to the blepharoplast of its side of the axostyle. From or near 

 the blepharoplasts arise three pairs of flagella. 



Fission in Giardia muris.} — C. A. Kofoid and B. B. Christiansen 

 have studied binary and multiple fission in this parasite from grey and 

 white mice and in Peromyscus, in which it causes chronic enteritis, 

 especially in young hosts, with inflation and yellowish discoloration of 

 the intestine. 



The normal trophozoite has a single axostyle, not two, as heretofore 

 stated, an integrated neuromotor apparatus with fibrillar connexions 

 joining the karyosomes, centrosomes, blepharoplasts, flagella, parabasal 

 bodies, and axostyles of the two cells in one more or less continuous 

 system. 



Binary fission occurs abundantly and normally, with delayed plas- 

 motomy. Normal mitosis occurs with an intranuclear spindle, and four 

 chromosomes in two groups. Precocious splitting of chromosomes in 

 the prophase is followed by their fusion into a split skein, from which 

 the four chromosomes emerge on the equatorial plate. The l)lepharo- 

 plast and axostyle lead in mitosis. 



* Ann. Inst. Pasteur, sxx. (1916) pp. 195-204. 



t Publications Univ. California (Zool.) xvi. (1915) pp. 23-9 (1 fig.). 



X Publications Univ. California (Zool.) xvi. (1915) pp. 30-54 (4 pis. and 1 fig.). 



