254 



DR JOHN RENNIE AND MR ALEXANDER RETD ON 



tissue in which there is a transverse row of ten or twelve excretory canals (fig. 18). 

 These merge in each other, converging to a terminal pore. Longitudinal sections show 

 the branches of the canals to be very numerous. 



The body of the cysticercoid consists of a peripheral and a central portion. The 

 former is limited by a well-defined, thick cuticle, contains numerous excretory vessels 

 (about 60 in transverse section) and a loose parenchyma. The central region contains 

 the muscular bulbs of the proboscides, and around these a well-developed mass of longi- 

 tudinal muscles (fig. 16). The central area at its posterior end merges into the 

 protrusible bulb (fig. 17). 



The question of the more exact identification of the species to which the form belongs 

 must be left undecided. 



G. E. Wa(;en'er (5) has described a similar form from Phycis mediterranea. 



LITERATURE. 



(1) Ariola, v., "Revisioiie della famiglia Bothriocephalidae s. Str.," A/rh. ParaMul., iii. No. 3, 1900. 



(2) Baird, Proc. Zool. Soc. London, 1853. 



(3) VON LiNSTOw, Jahrb. Hamb. Wissensch. Anst., ix. Jahrg., 1891. 



(4) Shipley, A. E., National Antarctic Expedition Rejwrts, 1907, "Cestoda," vol. iii. 



(5) Wagener, G. R,, Verhdlgn. (Nov. Act.) d. K. Leop.-Carol. Acad. d. Naturf., Bd. x.iciv. Suppl., 

 Breslau, 1854. 



(6) ZscHOKKE, Fauna Arctica, "Die Arktisclien Cestoden," Bd. iii., Licferung i., 1903. 



REFERENCES TO FIGURES. 



c. = cutioula. 

 c.s. = cirrus sac. 

 eKc.c. = excretory canals. 

 exc.h. = excretory bidb. 

 l.m. = lotigitudiual musculature. 

 «.c. = nerve cord. 

 0. = ovary. 

 per.a. = peripheral area. 



r.m. = retractor muscles of proboscides. 

 s.c. = sub-cuticula. 

 s7i.o«. = shelled ova. 

 t.f. = testes follicles. 

 ut. = uterus. 

 V. = vagina. 

 y.c. = yolk cells. 



EXPLANATION OF PLATES. 



Plate 1. 



Fig. 1. Transverse section of Dibothriocephalus scoticus, n. sp., at the level of the ovary. 



Fig. 2. (a) Entire specimen of D. scoticus ; (b) scolex of D. scoticus. 



Fig. 3. (a). Anterior end of Anchistrocephalus micrccephalus ; (b) immature proglottis of Anchistro- 

 ceplialus niicrocephalua. 



Fig. 4. Four specimens of Dibothriocephalus wilsoni, Shipley. 



Fig. 5. Scolex of Dibothriocephalus coatsi, n. sp. 



Fig. 6. Transverse section of D. coatsi. 



(rot. soc. edin. trans., vol. xlviil, 452.) 



