ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
601 
the chief communication between the coelom and the vascular system 
has been established. It seems fairly certain that it is not only by 
means of the botryoidal channels that the communication has been 
brought about. The botryoidal channels seem to be rather of the nature 
of a by-path, through which the htemolymph does not necessarily 
circulate. 
“ Whatever may be the process whereby the continuity between the 
coelom and vascular system has been established in the Gnathobdellidae, 
there can be little doubt that it is a secondary condition, and that the 
structure of such a form as Acanthobdella , in which a closed blood- 
system lies in a normally developed coelom, is really the more primitive.” 
Development of Segmental Organs.* — Herr R. S. Bergh, having 
obtained recently an abundant supply of Hhynchelmis material, has re- 
turned to the examination of the developing nephridia. He finds that 
the cells which later form the coil and excretory tube of the nephridium 
originate in a median and obliquely dorsal direction from the nephridio- 
blasts, while the four cells of the lower lip arise later from the nephri- 
dioblasts by equal division. The upper lip arises out of finely granular 
cells lying to the middle of the nephridioblasts. Vejdovsky’s “ vacuole ” 
appears to be merely a diverticulum of the segmental cavity. The 
author believes that his former statement as to the origin in Oligochaetes 
in general of funnel, coil, and terminal portion from a single primordium 
is true also of Bhynchelmis, but the funnel primordium is early differ- 
entiated into upper and under lip, and the coiled region grows out of 
the under lip. In general, Bergh does not find that his earlier statements 
require any modification on account of Yejdovsky’s work. 
Rotatoria. 
Rotatoria of Fresh- water Plankton.f — Dr. G. Marpmann (over the 
signature M.) gives a very brief, unsatisfactory, and in part inaccurate 
account of the class Rotifera, with a number of mistakes and misprints 
in the names, and classifications by Eifert and Daday which have not been 
accepted by any other student of the class. In speaking of Rousselet’s 
method of preserving Rotatoria, the author states that, after fixing, the 
animals are passed through 70 and 80 per cent, into absolute alcohol, 
and then into xylol and balsam. Surely the author must have been 
dreaming all this, for nothing of the kind is done in Rousselet’s method ; 
on the contrary, all contact with strong alcohol and balsam is carefully 
avoided. 
N ematohelminth.es. 
Unusual Expulsion of Ascaris lumbricoides.ij: — Dr. G. Alessandrini 
records two cases observed within a year ; the first of a lady from whose 
gullet he extracted a male worm ; the second of a child of four years 
in which the worm occurred in the trachea. Both were successfully 
treated. 
North American Gordiacea.§ — Dr. T. H. Montgomery publishes a 
useful list of the Gordiacea of the United States, with keys for the 
* Zeitschr. f. wiss. Zool.. lxvi. (1899) pp. 435-49 (1 pi.). 
t Zeitschr. f. angew. Mikr., iv. and v. pp. 105-112 and 139-42. ' 
L | i Boll. Soc. Rom. Stud. Zool., viii. (1899) pp. 83-4. 
§ Amer. Nat., xxxiii. (1899) pp. 647-52. 
