536 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
looked by all previous observers, was noted and figured by Hesse * in 
1892, and by himself (Shipley) f in 1894. 
Chromatin Reduction in Oogenesis of Ascaris.f— Herr M. Sabasch- 
nikoff has studied this much investigated subject in Ascaris megalocephala 
bivalens, and has reached the following conclusions : — 
(1) The chromatin thread of one piece, which is left by the last 
division of the oogonia (from the stage of the “ daughter-coil ”), divides 
in the oocytes of the first order into several threads, which subsequently 
fall into separate chromo-microsomes. 
(2) The chromo-microsomes begin to arrange themselves in groups of 
four. 
(3) These groups, apposed to one another, form in the nucleus a 
tetrapartito chromatin fibre, which may be called a provisional “ Vierer- 
gruppe.” 
(4) This divides transversely and forms two typical “ Vierergruppen .” 
(5) In the maturation processes two reducing divisions remove from 
the ovum three parts of each “ Vierergruppe” i.e. three-fourths of the 
total number of mierosomes. 
If these conclusions be correct, they corroborate Weismann’s version 
of the maturation process. 
Ascariasis. § — Dr. L. Valentini describes the case of a tramway 
horse in Rome which contained in its stomach and intestine 1142 speci- 
mens of Ascaris megalocephala , over a score of which had penetrated the 
intestinal wall into the peritoneal cavity, causing fatal peritonitis. 
Platyhelminth.es. 
Helminthological Notes.|| — Dr. M. C. Francaviglia describes Disto- 
mum Mans Rud., EcMnostomum spinulosum Rud., and Tsenia dodecantha 
Krabbe, which he found as parasites in Hydrocolseus minutus Pallas. 
Cysticercoids of Freshwater Crustacea. IT — Hr. A. Mrazek discusses 
some of the thirteen Cysticercoids which he has found in freshwater 
Crustaceans, devoting particular attention to those of Tsenia integra Ham. 
(in Gamarus), and of T. lanceolata Bl. (in Cyclopidte). 
Budding Cysticercus from Mole.** — Dr. A. Bott describes a remark- 
able form of bladder-worm found in a mole. It showed asexual multi- 
plication by means of external buds. The budding area lay posteriorly 
at the opposite end from the scolex, but in some of the bladders buds 
occurred all over. In most there were three to five buds, but in some 
cases as many as eighty spherical protrusions were counted. The various 
stages seem to show clearly that separation is effected by simple con- 
striction. The author describes the minute structure and discusses 
other cases of asexually-multiplying Cysticerci. He regards his discovery 
as most probably a variety of Cysticercus longicollis Rud. Since the 
paper was completed Braun ff has described a closely similar case. 
* Zeitschr. f. wiss. Zool., liv. p. 548. f Proc. Zool. Soc. London, 1894, p. 531. 
t Bull. Soc. Imp. Nat. Moscou, 1897, pp. 82-112 (1 pi.). 
§ Boll. Soc. Rom. Zool., vi. (1897) p. 177. || Tom. cit., pp. 118-24. 
^ SB. Iv. Bolim. Ges. Wiss., 1896, ii. No. 38, 16 pp. and 1 pi. 
** Zeitschr. f. wiss. Zool., lxiii. (1897) pp. 115-40 (2 pis.), 
tf Zool. Anzeig., xix. No. 514, and xx. No. 521. 
