THE TREMATODE PARASITES OF FISHES. 483 



Sub-Familv Haplocladtnae. 



Genus TERGESTIA Stossich. 



Tergestia laticollis (Molin). 



Odhner, 1911, p. 111-13 ; Nicoll, 1913b, pp. 192-3. 



This species was found frequently in the intestine of the horse-mackerel 

 (Trachurus trachurus). It occurs occasionally in fairly large numbers, 

 though as a rule only a few specimens are present in one host. It appears 

 to be an exclusive parasite of this host. 



Family ZOOGONIDAE. 



Sub-Family Zoogoninae. 



Genus ZOOGONOIDES Odhner. 



Zoogonoides viviparus (Olsson). 



Odhner, 1902a, p. 62 ; Nicoll, 1907, p. 83. 



This very common parasite has already been recorded^from eight 

 species of British fishes. An additional five have here to be noted, 

 namely, Zeus faber, Blennius gattorugine, B. ocellaris, Solea vulgaris, 

 S. variegata. It was also found in Callionymus lyra, Pleuronectes limanda, 

 P. microcephalus and P. plafessa. The chief hosts of this parasite are 

 undoubtedly Callionymus lyra, Pleuronectes spp. and Solea spp. It is 

 rather curious that it has never once been recorded from Gadoid fishes 

 or from the Labridae. It is worth remarking that the specimens I 

 obtained from the cat-fish {Anarrhichas lupus) at St. Andrews belong to 

 this species and not to the more recently discovered Z. suhaequiporus 

 Odhner, from the same host. 



Genus ZOONOGENUS Nicoll. 



Zoonogenus vividus Nicoll. 



Nicoll, 1912, pp. 200-2. 



A species which I have already described was met w^th frequently in 

 the intestine of Sparus centrodontus. As I have previously remarked, it 

 is an extremely delicate species and exceedingly difficult to preserve in a 

 satisfactory state. An additional six bream obtained from BilUngsgate 

 Market were examined in June, 1912, but they were not infected with the 

 parasite. 



