TRANSLATION. 
On the DrvetorpMENT of ASCARIS NIGROVENOSA. 
By E. C. Mrcznixow. 
(From Reichert and du Bois-Reymond’s ‘ Archiv,’ 1865, p. 409, pl. x.) 
In the following pages the anthor proposes to communicate 
the result of researches on the peculiar development of Ascaris 
nigrovenosa, which have been conducted in the laboratory at 
Giessen, and of which a brief report has already been given 
by Prof. Leuckart.* 
The fully developed worm, as is well known, inhabits the 
lungs of the brown frog (R. esculenta), and feeds upon its 
blood. 
The lips surrounding the mouth are but very slightly 
developed. Behind the oral orifice lies a minute cavity with 
chitinous walls, and usually regarded as the pharynx. To 
this succeeds the so-termed cesophagus, in the interior of which, 
besides the transverse striz, may be noticed opaque granules 
and clear nuclei. The cuticle of the body, as well as the 
subjacent muscular layer, are comparatively thin, a circum- 
stance which well accounts for the little mobility of the 
animal. The remainder of the cavity of the body is filled 
with numerous granules, either isolated or aggregated into a 
few common masses. 
Ascaris nigrovenosa deposits a great number of ova 0'013 mm. 
in length, and which contain fully developed embryos, whose 
development has been already described by Kolliker.t 
The fully formed embryos when liberated from the egg 
are 0°36mm. in length, and present the following charac- 
ters. They are cylindrical in form, tapering more behind 
than in front. The mouth is surrounded by a cuticular lip, 
and it communicates with an organ resembling the pharynx 
of the parent worm. The esophagus presents two enlarge- 
* « Helminthologische Experimental-untersuchungen,” 4 Reihe, ia ‘ Got- 
tinger Nachrichten,’ 1865, No. 8, p. 219. 
ft Miiller’s ‘ Archiv,’ 1843. 
VOL. VI.—NEW SER. Cc 
