30 S. GOTO. 



mesenchyma by a compact membrane of the nature of connective 

 tissue. 



Though closely allied to Galicotyle, the present genus presents 

 some peculiar feature in the structure of the posterior sucker. 



Posterim- sucker — This ha§ exactly the shape of a circular saucer, 

 and is attached to the body by a short stalk. It is provided with a 

 marginal membrane all round, which is exactly of the same nature as 

 that of the posterior suckers of DicUdopliora ; only its connective tissue 

 is more compact (PI. XVII, figs. 2, 4, and 5). A further difference is 

 that the membrane bears on its ventral surface numerous chitinous 

 projections arranged in radial series ; there being five of these chitinous 

 projections in each series (figs, 2, -i, and 5). The internal sur&ce of 

 the sucker is divided into eight equal secants by as many radiating 

 elevations, the positions of which are such that two of them coincide 

 with the median line of the body. These radial elevations also bear 

 on their surfaces each a series of chitinous pieces which are figured in 

 radial section in fig. 3 (PI. XVII), and in tangential section in fig. 8. 

 In the latter figure it appears as if these pieces have been formed 

 simply by local chitinisations of the investing membrane of the body. 

 These so-called chitinous pieces are deeply coloured by haematoxylin, 

 more deeply than the investing membrane. 



The muscular fibres of the sucker are very different in structure 

 from those hitherto described, and are all arranged, with an insiffni- 

 ficant exception, dorso-ventrally (PI. XVII, figs.4, 5, 7, and 12). They 

 are striped, and a single fibre traverses the whole thickness of the 

 sucker. Each fibre (about 0.01 mm. thick) consists of very refractive, 

 narrow zones, which deeply stain in haematoxylin, alternating with 

 broad, non-refi-active zones, which are but slightly stained with 

 haematoxylin and are finely but distinctly striated longitudinally. 

 Each of these non-refractive zones is again crossed at its middle by 



