276 s. GOTO. 



It apjiears, therefore, that two species must be recognized 

 under the name of 0. scombri, viz., 0. major Goto and 0. 7ninor 

 Goto. Unfortunately the original paper of Kuhn ['29] is not 

 accessible to me, and I can not decide to which species his 

 specimens should be refened. If, however, his description and 

 figures should prove insufficient to decide the present question, 

 I should propose to retain the name of 0. scombri for my 

 0. major* It goes without saying that the former name should 

 then also appear as a synonym pro parte of 0. minor. 



It may be added in conclusion that the posterior hooks of 

 the specimens of 0. inajor from the mackerel taken off Newport, 

 measured 0.112 mm., a figure almost coinciding with the one 

 obtained for 0. 7najor ['94, p. 203]. 



Polystonium Hassalli n. sp. 

 (PI. XXI, figs. 16 & 17). 



Total length of the body 1.5 mm., body proper ovate; ad- 

 hesive disc hexagonal, the hemispherical suckers occupying the 

 angles of the hexagon, and each with a minute hook in the 

 centre (fig. 17 ô) ; with three pairs of hooks between the most 

 anterior pair of suckers, and two pairs between the most posterior, 

 these hooks and those in the suckers being all of the same form 

 and measuring 0.33 mm. in length. The larger hooks between 

 the most posterior suckers bifurcated towards the base, without 

 any lateral process, measuring 0.125 mm. in length. Anterior 

 sucker large. Oesophagus wanting ; intestine bifurcated, tubular, 

 without lateral branches, the two legs ending independently at 

 the front end of the adhesive disc, and together enclosing an 



* Following Articles 35 and 36 of the " Kègles de la Nomenclature " adopted by the two 

 er national Congresses of Zoology held in Paris and Moscow. 



