BY W. A. IIASWELL. 53 



The eggs (fig. 7) are elliptical, about 0-08 mm. in long diameter. 

 They are thus larger than those of most segmented Cestodes, l3ut 

 considerably smaller than those of G. ruyosa, which measure 

 0*1 mm., and are the largest Cestode eggs the dimensions of which 

 have been recorded. In G. nigrosetosa a circular area of the shell 

 at one pole is much thinner than the rest, and is probably 

 differentiated as an operculum. At the opposite pole there is 

 occasionally, though by no means frequently, a filament, usually 

 very short. Coalescence of two eggs by fusion between their 

 shells is by no means rare. No hooked embryos are present in 

 either of the specimens. 



In my specimen of G. rugosa the eggs differ from those of G. 

 nigrosetosa not only in size, but in the appearance of the shell, 

 which does not appear to be provided with an operculum. 

 Hexacanth embryos are abundant, and are remarkable for their 

 large size and the comparatively colossal dimensions of their 

 hooks. These are disposed in pairs like those of hexacanth 

 embryos in general. In G. uima Lonnberg failed to find any 

 hooks, and this circumstance, when we take into account the fact 

 that the observer in question had abundance of material at his 

 disposal, would seem to jDoint to an important difference between 

 the two species with regard to the structure of the embryo. 



LITEEATUEE. 



1. — Benham, W. B. — " A Treatise on Zoology," edited by E. Ray Lankester. 



Part iv. " The Platyhelmia, Mesozoa and Nemertini " (1901). 

 2. — Braun, M. — " Gyrocotyle, Amphiptyches u. Verwandte." Central- 



blatt f. Bakteriologie u. Parasitenkunde. vi. Bd. (1889). 

 3. "Vermes" of Bronn's " Klassen u. Ordnungen des 



Thierreiehs." 

 4. — LoENXBEKG, EixAR — " Anatomlsche Studien liber Skandinavische Ces- 



toden." Kongl. Svenska Vetenskaps-Akademiens Handlingar, 



Bd. 24. 

 5. — MoNTicELLi, F. 8.— "Sul sistema nervosa dell' Amphiptyches urna." 



Zool. Anz., 1889. 

 6, " Appunti sui Cestodaria." Atti della E. Accad. dell Scienze 



lis. e nat. di Napoli, 1892. 



