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 Polyphemede, 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 larve,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, 1 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, sufticiently 
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 leuckartt. 
* Annals of Scottish Natural History, April, 1892, p. 142. 
DESCRIPTION OF THE PLATES. 
PLATE XVII.. 
ELudactylina minuta. Diam 
Fig. 1. Female, side view, ABS 
Fig. 2, Female, dorsal view, x. ak 
Fig. 3. Antennule, x S21 
Fig. 4- Antenna, x 521 
Fig. 5. First maxilliped, x §21 
Fig. 6. Second maxilliped, , : x 3890 
Fig. 7. Foot of first pair, ‘ : ‘ x 521 
Fig. 8. Foot of second pair, : ‘ x 260 
Fig. 9. Foot of fourth pair, x 260 
Fig. 10. Foot of fifth pair, x 260 
Fig. 11. Furcal joints and last two segments of abdomen, x 260 
Lerne lusct. 
Fig. 12. Female, side view, 5 : : . ee 
Fig. 13. Parasite on gill of Gedus luseus, ‘ ; . + i 
Trematodes. 
Fig. 14. Thaumutocotyle concinna, : : 2 : 5s eee ae 
x 
Fig. 15. Heterocotyle pastinace, 
Fig. 16. Larval fish with two specimens of Podon leuckarti attached to it, x 39°75 
