of the Fishery Board for Scotland. 



89 



minute head, and the readiness with which the low T er "joints " (proglottis), 

 separated from each other. The longest example I obtained measured 

 fully nine feet, and appeared to be fairly complete. Another specimen 

 reached to about seven feet in length, and there were a number of smaller 

 pieces. 



The proglottides or "joints" near the middle and towards the posterior 

 end of the larger specimens measured from ten to twelve millimeters in 

 width and nearly the same in length. The head or scolex seen in profile 

 is very compressed, but viewed in front its outline is somewhat triangular, 

 and the suckers — two in number — occupy the two sides of the triangle, as 

 shown hi the drawing (fig. 6, Plate V.). The neck is extremely slender, 

 measuring only about -08 mm. in width. 



There appears to be very little known concerning the life-history of this 

 Cestode, but probably in its larval stage it lives encysted in the body of 

 some species of fish such as the whiting, considerable numbers of which 

 are sometimes captured by this Cetacean for food ; the Cestode being in 

 this way introduced into the stomach of the Porpoise would obtain its 

 freedom and be able ere long to attain to sexual maturity in the intestine 

 of its new host. 



Figure 1, Plate VII., is from a photograph, about natural size, of the 

 largest of the specimens of the Diphyllobothrium, from the Porpoise 

 referred to. The Cetacean was obtained in May 1900. 



(2) On Nematodes or Threadworms observed in the stomach and 

 other viscera of a common porpoise. 



In another Porpoise obtained on June 18th, 1902, under much the same 

 conditions as the one mentioned above, no Cestodes of any kind were 

 observed, but in the stomach and some of the other internal organs many 

 small threadworms were noticed. The length of some of these measured 

 between forty-five and fifty millimeters, but the majority were considerably 

 smaller. The worms occurred in abundance in the stomach and other 

 portions of the viscera, and were of a dull reddish-brown colour. 



Strongyloid Nematodes, known as Lung -worms, are found parasitic in 

 the Common Porpoise ; they are all viviparus. Three species have been 

 recorded, Prosthecosacter inflexus, Diesing, measuring 6 to 9 inches in 

 length ; P. minor, Diesing, the length of which is about an inch ; and 

 P. convolutus, Diesing, the length of which may extend to a little over 

 one and a half inches (18-20 m ). 



Dr. Cobbold, referring to these worms, states that when "they are 

 examined in a fresh state the young may occasionally be seen escaping 



from the vagina, that Professor van Beneden noticed this 



phenomenon in Prosthecosacter inflexus, and the same was observed by 

 Busk in P. convolutus. " * 



The Entozoa from the Porpoise examined at the Laboratory in 1902, 

 like those mentioned above, are apparently also viviparous, and they agree 

 fairly well with the species last named — P. convolutus, Diesing. 



Though the specimens when removed from the Porpoise were still alive, 

 they had to be put into preservative fluid straight away, and therefore I 

 had not the good fortune to observe the phenomenon referred to by 

 Cobbold. Afterwards, however, when a few of them were dissected, fully 

 formed larvse were obtained in considerable numbers. 



Figure 13, Plate V., represents the posterior portion of a female 

 specimen showing the larvae in situ. Figures 13 a., b., and c. represent three 



* Entozoa of Man and Animals, p. 423. 



