Miscellaneous. 509 



met with ; and it is in this state especially that the ph}'sician should 

 be able to recognize them. At this time they are 0-3'3 millim. in 

 length and 0*022 millim. in breadth. The oesophagus shows its 

 characteristic form very well, resembling a pestle with two heads, 

 one cylindrical, the other spherical. The intestine contains fatty 

 globules, no doubt derived from the milk which constitutes the 

 patient's diet. The uterus only appears in the form of a vesicle on 

 the right side of the animal ; the vulva is not yet open. 



Five days suffice for the Rliahditis stercoral'is to attain its com- 

 plete development under favourable cii'cumstances ; hence its ex- 

 treme abundance in the intestines of the patients. 



In fine, this Nematode, very nearly allied to Rliahditis terricola, 

 Duj., so well described by M. Peres, differs from the latter in its con- 

 stantly smaller size, but especially in the form of the penial appa- 

 ratus, which is moreover destitute of cirri and of the caudal hood. 



Dr. Normand has met with this parasite in the stomach, in the 

 whole of the intestine, in the pancreatic duct, the gall-duct, the 

 hepatic ducts, and on the walls of the gall-bladdei'. — Comptes 

 Rtnidus, October 9, 1876, p. 694. 



On the intimate Phenomena of Cell -Division. By M. H. Fol. 



In my memoir on the Geryonidse I gave the first exact description 

 of these phenomena, which previously had not been understood either 

 by botanists or zoologists. All the principal points in those pro- 

 cesses, such as have been since made known in more detail, were 

 contained in the above-mentioned description. My observations 

 were soon confirmed by the independent works, posterior to mine, 

 of MM. Flemming and Biitschli ; and my theoretical ideas have 

 received valuable support from M. Flemmiug and especially from 

 M. Bobretzky. 1 have now to communicate the results of the in- 

 vestigations I have just made upon segmentation in the Heteropoda, 

 the Echini, and in Sagitta, which appear to me fitted to lead to the 

 modification of the ideas accepted by most recent authors. 



The centres of attraction appear, before each segmentation, at the 

 two opposite poles of the nucleus, which is still absolutely intact, 

 and seem to be a local fusion of the substance of the nucleus with 

 the vitelline protoplasm, or perhaps an irruption of the protoplasm 

 into the more fluid interior of the nucleus. To these two small 

 aggregations of sarcode, rays of sarcode immediately run, some of 

 them extending in the interior of the nucleus from one centre of 

 attraction to the other, whilst the other rays diverge in the vitellus. 

 I first described this formation of rays in Pteropoda ; and M. Bo- 

 bretzky has arrived independently at perfectly concordant results, 

 in his remarkable memoir on the embryogeny of the Gasteropoda. 

 M. Biitschli ascribes especial importance to the intranuclear fila- 

 ments, to which he gives the name of fibres ; whilst the filaments 

 which lose themselves in the vitellus are regarded by him merely as 

 striaj. This distinction is founded especially on the diff'erent asj^ect 

 of tliese two kinds of filaments, a difi'erence which is quite naturally 

 explained if we consider that the intranuclear filaments are im- 

 mersed in a nearly fluid medium much less refractive than the proto- 



Ann. & Mag. N. Hist. Scr. 4. Vol. xviii. 35 



