32 



s. GOTO. 



As has already been mentioned, the striped fibres are also present 

 in the postericn- pa.rt of the body (PI. XV 11, fii^-. 5), and this portion 

 is, as in tlie sucker, sharply separated from the sarnxinding- part by a 

 disiinct mendrrane (if connective tissue (fig's. 5 and 12). 



The striped muscular fibres have hitherto been observed, so far as 

 I knoAY, only in the sheath of the proboscis of Tctmr]\ynclmi<^^ among 

 the l^latlielminthes. 



Tristommn — As is well known, the anterior michrs are, in this 

 genus, situated in a pair near the unterior extremity of the body, on 

 both sides of the mouth or a little before it. They are more or less 

 circular, sometimes perfectly so und sometimes a little elliptical. 

 Internally the subst;uice of the suckers is directly continuous with the 

 mesenchyma of the body, and the suckers nve therefore to be regarded 

 merely as local expansions of the body. This view is strengthened by 

 the fact that the muscular fibres of the suckers are the direci continua- 

 tions of those of the body. The dorso-ventral fibres are arranged 

 exactly as in the body, with the only difference that they are here more 

 strongly developed in accordance with their task as the chief agent 

 of suction (PL XXIT, fig. 5). The longitudinal and diagonal fibres, 

 on entering the suckers, become more or less intermingled Avith each 

 other ; Init the former mostly radiate straight towards the ])eriphery, 

 while the latter curve round, and are mostly arranged more or less 

 concentrically with tlie cii'cumference of the suckers ; the terminations 

 of both tlie groups of fibres being attached to the investing membrane 

 on the dorsal as well as on the ventral side. The circular fibres of the 

 body also enter the suckers ; but they here lose their typical arrange- 

 ment, and become interminu'led with the diaoronal fibres. 



1). Piutuer — Untersuchungen il. d. Bau des Baudwuruikörpers. Wiener Arbeiten, Bd. 3, 

 2. lift., 1880. p. 50. 



