280 



Part III. — Twenty -second Annual Report. 



But although such incidents are not of rare occurrence among the 

 Entomostraca, the example to which I would direct attention, where a 

 post-larval fish is apparently being attacked by two members of the 

 family Polyphemedae, is somewhat unusual. Larval and post-larval fishes 

 have no doubt many enemies, among which may be included other fishes 

 as well, and it has also been shown that even the harmless-looking 

 Sagittae feed upon such larvae, t but this is the first time I have observed 

 Entomostraca presumably attacking a post-larval fish in the manner 

 shown by the drawing. 



As stated in the preliminary note, I am indebted to Dr. Williamson 

 for this interesting specimen. The fish, he tells me, is a Pleuronectid — 

 probably Pleuronectes platessa — but its emaciated condition made its 

 correct identification somewhat doubtful. That these Crustaceans have 

 become accidentally attached to the specimen is hardly likely, for the 

 position they occupy and the firm hold they have of the fish, evidenced 

 by their adhering while extraneous matter was being brushed off, and by 

 their continuing to adhere firmly though subjected to a good deal of 

 tossing about, does not favour such an explanation, but tends rather to 

 support the opinion that they have intentionally seized hold of the young 

 Pleuronectid, but whether for the purpose of attacking or merely for 

 resting I am not prepared to say. The specimen is, however, sufficiently 

 interesting to be recorded here. The fish was observed in a tow-net 

 gathering collected last year and supposed to be from the North Sea. 

 The two Crustaceans belong to the same species, viz., Podon leuckarti. 



* Annals of Scottish Natural History, April, 1892, p. 142. 



DESCRIPTION OF THE PLATES. 



PLATE XVII.. 



Eudactylina minuta. 



Fig. 1. Female, side view, 



Fig. 2. Female, dorsal view, 



Fig. 3. Antennule, 



Fig. 4- Antenna, 



Fig. 5. First maxilliped, 



Fig. 6. Second maxilliped, 



Fig. 7. Foot of first pair, 



Fig. 8. Foot of second pair, 



Fig. 9. Foot of fourth pair, 



Fig. 10. Foot of fifth pair, 



Fig. 11. Furcal joints and last two segments of abdomen 



Lernce lusci. 



Fig. 12. Female, side view, ....-• 



Fig. 13. Parasite on gill of Gedus luscus, .... 



Trematodes. 



Fig. 14. ThaumatocotyU concinna, . 



Fig. 15. Heterocotyh pastinacce, . . 



Fig. 16. Larval fish with two specimens of Podon leuckarti attached to it, 



Diam. 



X 



79-5 



X 



61 



K 



021 



X 



521 



X 



521 



X 



390 



X 



521 



X 



260 



X 



260 



X 



260 



X 



260 



X 



9 



X 



3 



X 



95-5 



X 



53 



X 



39 75 



