152 DR. w. c. m'intosh on the food and 



curred — both in the small intestines. The more perfect one had 

 its head retracted and quite loose. The entire animal was about 

 half an inch in length. Continuous with the base of the proboscis 

 was an elongated muscular structure, possessing many longitudinal 

 striae. Attached to this were many muscular bands slanting 

 backwards. In the space behind the sac were also many cellular, 

 granular, and crystalline masses. Rather behind the middle of the 

 animal were two elliptical testes, granular and opaque. Posterior 

 to these lay the ordinary granular and cellular structures, besides 

 a convoluted tubular organ, at whose termination was an ovoid mass 

 with a coiled aspect. This was succeeded by a peculiarly convoluted 

 structure shaped somewhat like tlie semicircular canals of the in- 

 ternal ear, and followed posteriorly by a barred curved portion 

 which lies a little in front of the termination of the animal*. 

 The investing structure formed a thick layer, marked here and 

 there by many mottled and shaded portions. When the hooks of 

 the creature are fixed in the mucous membrane, it is impossible to 

 remove them without tearing the texture therewith, as may be 

 readily imagiued from their form and direction. 



Bothriocephalus prohoscideus (End.) was the only species met 

 with ; but it occurred in by far the greater majority of the grilse 

 and salmon, generally commencing with its coils in the duodenum 

 and pyloric caeca, and stretching down the gut. The heads were 

 generally met with in one of the caeca ; and the appearance of the 

 various specimens was very similar, except that some (probably 

 owing to peculiarity of pressure) showed a greater bulging of the 

 outliae just behind the anterior end. The following may be given as 



transformations in its passage fi-om the embryonic to the adult condition, — the 

 embryo bearing a relation to the fully- developed wonn similar to that which 

 Pluteus and Pilidium respectively bear to Ophiurus and Nemertes. Dr. Guide 

 Wagener's previous investigations had led us to believe in a more simple and 

 direct mode of development (Siebold and KoUiker's Zeitschrift, 1857, vol. ix. 

 p. 77) ; but Leuckart fully estabhshes the fact of a true alternate generation in 

 the hfe-history of Eehinorliynchus. See his " Helminthologische Experimental- 

 untersuchungen " in Reports of Konigl. Gesellschaft der Wissenschaft. for Oct. 

 22nd, 1862.— T. S. C] 



* [The author's description here evidently vcievsio the ^ pavilion terminaV of 

 Dujardin, so efBciently described and figured by him in the ' Histoire NatureUe 

 des Helminthes ' as it occurs in the Hchinorhynchus Anthuris of the newt. This 

 copulatory apparatus of the male Echinorhynchus has since been noticed by 

 sevei-al authors, whilst the female organs of reproduction have been carefully 

 examined by ourselves (Linn. Trans, vol. xxii. p. 163), and especially also by 

 Dr. Guido Wagener, whose descriptions appeared in the 9th volume of Siebold 

 and KoUiker's Zeitschi-ift.— T. S. 0.] 



