^.4 



S. GOTO. 



which T li;ive iii-iinly directed my attention in tliis respect, tlie 

 arr.ing-ement of the muscular fibres of the posterior sucker is somewliat 

 different from that descril)ed by Niemic.'^ The fibres may be dis- 

 tinguished into f(jur groups. (1) The radial fibres. These must again 

 be distinguished, as in Calicotjilc, into two subgroups : (rt) tliose that 

 are direct continuations of the longitudinal fibres of the l)ody, and 

 entering the sucker, diverge irregularly in all directions, a.nd are 

 inserted to the periphery of the sucker. They nnjreover cross each 

 other in the stalk of the sucker ; those coming from the two sides 

 of the body going to the opposite sides of the sucker (PI. XX, fig. 5). 

 (/v) Those fibres that ai*e confine*! to the radiating spokes. These start 

 fi-om the margins of the central ])olygon, and running in small bundles 

 along the spokes just under the investing membrane, are inserted, 

 likewise, in the periphery of the sucker (PI. XX, fig. 7, rail. miis. h.'). 

 (2) The circular fibres, /. c, those that riui conceritrically with the 

 circumference of the sucker. This group must also be divided into 

 two sub-groups, (a) Those that belong to the ^entral side. These 

 are arranged in two sets, an outer and an inner. The fibres of the 

 outer set are arranged in a single layer ; while those of the inner set 

 are uiiited into strong bundles, which are separated from one another by 

 the trans\erse fibres to be described presently, and from the outer set 

 b}^ an inter^'ening layer of mesenchyma (PI. XX, fig. 0, cir. 7;^^^s■.). 

 The circular fibres of the dorsal side s u'e arranged in a single layer, and 

 occupy an exactly similar position to that of tl>e outer set of the ventral 

 side, (o) The transverse fibres, i.e., those that traverse the thickness of 

 the sucker, and run therefore at riij-ht ano-Ies to its two surfaces. 

 They are, in Tr. siniiatinu, very strongly developed, and, like 



1). Xiemic— Recherches morphologiques sur les ventouses dans le règne animal. Recueil 

 zoolog. suisse. T. II, 1835. I have not been able to gain access to this paper, and am indebted 

 for its account to Braun's " Würmer " in Bronn's " Klassen u. Ordnungen " and to Monticelli's 

 " Saggio di una morfologia dei Trematodi." 



