INTERNAL PARASITES OF THE SEBAGO SALMON. 1165 



Much later than the work just outlined is a paper by Tosh (1905) in which 

 he discusses his work on the internal parasites of the Tweed salmon. The mate- 

 rial was collected in 1895 at a single place. The author notes the distinctly 

 marine character of the parasitic fauna of this salmon, attributing it to the fact 

 that " salmon do not feed in the fresh water of a short river like the Tweed, except 

 under extraordinary conditions, when a prolonged stay is imposed upon them." 

 In all he lists 15 species, as follows: 



Ascaris capsularia Rudolphi. 

 Ascaris acuta Miiller. 

 Ascaris obtusocaudata Zeder. 

 Distoma varicum Rudolphi. 

 Distoma ocreatum Rudolphi. 

 Distoma miescheri Zschokke. 

 Echinorhynchus acus Rudolphi. 

 Echinorhynchus proteus Westrumb. 

 Echinorhynchus angustatus Rudolphi. 

 Bothriocephalus infundibuliformis Rudolphi. 

 Tetrarhynchus grossus Rudolphi. 

 Tetrarhynchus macrobothrius Rudolphi. 

 Tetrabothrium minimum (larva). 

 Tetrabothrium sp. (larva). 

 Taenia sp. (larva). 



Details are given concerning the frequence, appearance, and biology of 

 each form. The most important is held to be Bothriocephalus injundibulijormis, 

 which, according to an appended table, occurs in 26.4 per cent of the 892 fish 

 examined. It does not seem, in the opinion of Tosh, to be seriously harmful to 

 the host and is found in the largest and best-fed fish in numbers ranging from 

 I to 6 per host. The tremendous infestations noted by Zschokke apparently do 

 not occur in this region in the salmon, although observed in the sea trout. 



The only notices from Ireland concerning salmon parasites are brief and 

 also of long standing. Drummond (1838), writing in Belfast, described Tetra- 

 rhynchus grossus from the abdominal cavity of the salmon, which he found only 

 once, and Tetrarhynchus solidus, new species, from the peritoneum and mesentery, 

 which he took from three salmon in July, 1838. 



Somewhat later Bellingham (1844) listed among the entozoa indigenous to 

 Ireland the following taken from the salmon, namely: 



Ascaris capsularia, on the peritoneum; also in 14 other species of fish, 

 all marine. 



Ascaris clavata, from intestine and peritoneum; also in 9 other species of 

 fish, all marine. 



Distoma ■varicum, from the stomach; common in some localities and seasons, 

 rare in others. 



Tetrarhynchus grossus, from the abdominal cavity ; entered in this list on 

 the authority of Drummond (1838). 



