Single, immature specimens of cestodes were foirnd in the 

 intestines of three sea lampreys; t"vro of these tapeworms were 

 identifiable — the third was not. Identified from th? scolex only, 

 ■vvas a plerocercoid larva of Trianophonis ( crassus ?).^^ Larval cysts 

 of Trianophorus crassus are found frequently, and occasionally in 

 some abundance, in the flesh of the whitefish and tullibee (Cameron, 

 19h^; Kennedy, 19hQ) • It has been observed that sea lampreys are 

 now feeding extensively on whitefish in northern Lalce Huron. Pre- 

 sumably, then, this larval tapeworm is traceable to this source. 

 It is considered doubtful if it (the plerecercoid larvae) could 

 mature since the sea lamprey is an unnatural final host for it. 



The other identifiable tapeworm ivas an immature specimen of 

 Ab othrium sp.v This parasite infects trouts, coregonids, and smelt 

 (Plehn, I92U) and burbot (Van Cleave and Mueller, 193^1 Bangham, 

 I9I4.6). Hovrever, since the larvae are normally found imbedded in 

 the intestinal wall of hosts, the manner in which the sea lamprey 

 carrying this parasite became infected is someivhat obscure. 



Occasional sea lampreys were taken in 19U7 and 19li8 Ti/hich had 

 small tumor-like cysts in the wall of the intestine. Five such 

 specimens were taken from Carp Creek in 19h7 (lj599 sea lampreys 

 examined) and 11 similarly afflicted specimens from the same stream 

 in 19U3 (2,933 sea lampreys examined). The majority of these swell- 

 ings were examined and proved to be cysts. However, in each case 

 the contents of the cysts were in a disintegrated condition and 

 could not be identified. The circumstances suggest strongly that 

 these cysts were those of nematode larvae ivhich had died^ according 

 to A. E. Woodhead (verbal communication). 



Although a large percentage of the total sample of sea lampreys 

 contained internal parasites of one form or another, no single 

 specimen contained enough parasites to constitute a severe or appar- 

 ently harmful infection. 



Occasional sea lampreys talcen in the Carp Creek trap in 19U8 

 had leeches attached to them. One of these, identical with the 

 others observed, was identified as Piscicola milneri (Verrill, 



N^ Identified by Prof. A. E. Woodhead, Dept. of Zoology, University 



of Michigan, 

 x^ Identified by Prof. A. E. Woodhead, Dept. of Zoology, University 



^f Michigan. 

 \/ Identified by Dr. Marvin Clinton Meyer of the University of Maine. 



- 68 - 



