176 



parent leech by their anterior suckers. It is quite true that the newly 

 hatclied young, if prevented from attaching themselves to the parent, 

 become fixed to each other in pairs by means of these glands ; but their 

 real purpose is to fix the young to the mother at a time when neither 

 sucker is sufficiently well developed to serve this end. Later they attach 

 themselves by the posterior sucker. 



Mus. Comp. Zool., Cambridge, Mass., Jan. 1, 1886. 



in. Mittheilimgen aus Museen, Instituten etc. 



1. Linnean Society of London. 



4th March 1886. — A paper was read Description of Strongylus Arnßeldi, 

 with observations on Strongylus tetracanthus by Prof. Spencer J. Cobb old. 

 Of Arnfield's Strongyle he drew attention to the morphology of the hood 

 and its rays, to the position of the vulva, and to the structure of the embryo. 

 He afterwards contrasted these peculiarities with those of allied forms. Re- 

 garding his observations on the Four-spined Strongyle, the following are his 

 conclusions: — (1) The eggs are expelled from their parent in a state of 

 fine yolk -cleavage. (2) The embryos are formed after egg expulsion, and 

 in a few days escape from their envelopes, undergoing a primary change of 

 skin in moist earth during warm weather. (3) As rhabditiform nematoids 

 they enjoy a more or les prolonged existence, probably living many weeks in 

 this state. (4) In all likelihood an intermediary host is unnecessary. (5) The 

 rhabditiform larvae are passively transferred to the intestinal canal, thence 

 they enter the walls of the cœcum and colon, encyst themselves, and accor- 

 ding to Leuckart, undergo another change of skin. (6) Their presence in 

 the intestinal walls is associated with pathological conditions Avhich fre- 

 quently prove fatal to the bearer, sometimes creating severe epizooty. 

 (7) Ordinarily the young worms perforate their cysts and migrate to the 

 lumen of the bowel, where they already afford external indications of sex 

 (Trichonema stage of growth). (8) They next form Cocoons by the agglutina- 

 tion of Vegetable debris within the gut and undergo a third ecdysis, atten- 

 ded with intestinal metamorphosis. (9) The formation of the internal sexual 

 organs and the completion of the definitive form is acquired within the colon 

 of the host. — J. Murie. 



Bemerkung. 



Um Irrthümer bei Herstellung von Sonderabdriicken zu ver- 

 meiden, Averden die Herren Mitarbeiter ersucht, die Zahl der etwa 

 gewünschten Separate mir gleich auf dem Manuscript selbst 

 anzugeben und auch thunlichst gleichzeitig der Verlags- 

 handlung von "Wilhelm Engelmann mitzutheilen. Nachträg- 

 liche, d. h. nach Ausgabe einer Nummer, eingehende Bestellungen 

 können nicht mehr berücksichtigt werden. 



Leipzig. J. Victor Cams. 



Druck von Breitkopf & Härtel in Leipzig. 



