30 s. GOTO. 



mesenchyma by a compact membrane of the nature of connective 

 tissue. 



Though closely allied to Calicot ijle, the present genus presents 

 some peculiar feature in the structure of the posterior sucker. 



Fosterior sucker — This has exactly the shape of a circular saucer, 

 and is attached to the Ixjdy l)y 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 DicUdopliom ; only its connective tissue 

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

 that the membrane Ijears on its ventral surface nuniennis chitinous 

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

 projecti(jns in each series (figs, 2, 4, and 5). The internal surface of 

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

 elevations, the positi<nis 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. o (PL X^^II), and in tangential section in fig. 8. 

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

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

 These so-called chitintjus pieces are deeply coLjured by haematoxylin, 

 more deeply than the investing membrane. 



The nuiscidar fibres of the sucker are very différent in structure 

 fr<jm those hitherto described, aud are all arranged, Avith an insigni- 

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

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

 sucker. Each filjre (about 0.01 nun. thick) consists of very refractive, 

 narrow zones, which deeply stain in liaem;itoxylin, alternating Avith 

 broad, non-refractive zones, which are but slightly stained Avith 

 haematoxylin and are finely but distinctly striated longitudinally. 

 E;ich of these non-refractive zones is again crossed at its middle by 



