70 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



It is perhaps worthy of note that in the case of Caligus curtus the hosts 

 are entirely among the Gadoid fishes for both adult and chalimus stages. In 

 this species there was practically no variation in the number found on the 

 various forms of fish during different times of the season, Caligus rapax was 

 found on a greater variety of fish and also in greater numbers on the host. As 

 many as twenty-seven were collected from one fish, whereas the number of 

 C. curtus rarely exceeded six per fish. C. rapax was also obtained from the 

 Eel pout {Zoarces anguillaris) a host from which it has not yet been reported^ 

 This latter species was first noticed in small numbers towards the end of June, 

 but by far the greater number were collected during the months of July and 

 August. 



Comparativeh' few chalimus stages were found and in many instances 

 it was difficult to determine to which species the form belonged. The chalimus 

 stages of C. curtus were obtained from the Cod and Tomcod, while those of 

 C. rapax from the Cod and Lumpsucker, chiefly from the latter, nine being col- 

 lected from one specimen. Forms apparently belonging to the latter species 

 were also collected from the Hake and Haddock. The chalimus stages were 

 noticed particularly at two different periods — during the latter part of June 

 and during the last week of August. 



A large number of measurements were taken in order to ascertain whether 

 there is any variation in size in the various forms throughout the season. Practi- 

 cally none whatever in either species was found. In the case of C. curtus the size of 

 the parasite seemed to increase with the size of the host. The largest speci- 

 men of C. curtus obtained which was a male, was found to be 13.2 mm. and 

 the female 11.8 mm. in length. It might be added that in the adult fe- 

 male only in a very few instances was the abdominal segment found to be longer 

 than half the length of the genital segment — a marked difference from the find- 

 ings of Dr. C. Branch Wilson, who in his report states the opposite to be the case. 

 The largest specimen of C. rapax collected were female 6 . 4 mm. and male 5 mm. 



In conclusion it might be added that these fish whose activity was im- 

 paired by disease or which are naturally slow in their movements appear to be 

 particularly infested with the parasites, affording special opportunities in the 

 chalimus stage to become attached. This is quite evident in the case of the 

 Lumpsucker which lives among the seaweed and debris on the surface of the 

 water and is particularly sluggish in its movements. 



2. Argulidce. 



The fish were also examined for these parasites at the same time as the 

 Caligids were being investigated. For the major part of the work credit must 

 be given to Mr. N. A. Wallace who at the beginning of the season carried on 

 all the collecting in this direction. 



Only one species, Argulus fundulus (Kroyer) was found and this on three 

 different hosts, Pseudopleuronectes americanus (Miimimchog) , Heteroclitus fundulus 

 (Mummichog) and Pygosteus pungitius (Nine-spined Stickleback). 



