180 SUMMARY OF CURRENT RESEARCHES RELATING TO 



had apparently just come from the sea. To test this point, a trap was 

 set in these months the following year in the outflow. This trap had 

 its opening facing down-stream, to intercept eels coming up from the 

 sea, and in eight days it contained eighty-nine small eels of the same 

 size as those taken in the gate-house trap the previous year. The take 

 in the gate-house trap decreased in proportion, but the author remarks 

 that it remains to be seen whether the entire absence from the lake of 

 eels, which are excellent scavengers, may not affect the water prejudicially. 

 To test their capacity for living without water, a number of eels 

 were put into a box in a room at a temperature of 56° F. Two put 

 back into the water after twenty-two hours became quite active at once, 

 and the rest seemed in the same condition. The largest lived for forty- 

 three hours. Experiments made later in the season showed that eels 

 fifteen to eighteen inches in length can do without water longer than 

 small ones. One of these lived for seventy-two hours. Eels move 

 easily through wet grass, and " it is probable that they can travel over- 

 land for considerable distances, should occasion require it." 



Char of Great Britain. * — C. Tate Eegan discusses the British 

 species of Salvelinus. Four have been hitherto recognised — S. killinensis 

 from Loch Killin, S. struanensis from Loch Bannoch, S. willughbii 

 from Windermere, S. perisii from Llanberis. To these are added five 

 new species — S. gracillimus from Girlsta, Shetland, S. inframundus 

 from Hellyal Lake, Hoy Island, Orkneys (1862), S. maxillaris from a 

 loch near Ben Hope, Sutherlandshire, S. mallochi from Loch Scourie, 

 Sutherlandshire, S. lonsdalii from Haweswater. 



Tunicata. 



Phosphorescence of Pyrosoma.f — Charles Julin finds that isolated 

 ovarian ova and isolated embryos are phosphorescent. The luminosity 

 has two distinct and consecutive seats — in the first place, in the " testa- 

 cells," and, in the second place, in the lateral glands of the four primary 

 ascidiozooids. The " testa-cells " or kalymmocytes have no share in 

 forming the embryo ; they are not absorbed by the blastomeres. Their 

 structure is the same as that of the elements in the lateral glands, and 

 they cause phosphorescence in the cyathozooid. 



INVERTEBRATA. 



Mollusca. 

 i 5. Liamellibranchiata. 



Branchial Eyes of Bivalves. $ — Paul Pelseneer called attention in 

 1899 to the presence of a minute eye at the base of the most anterior 

 filament of the internal plate of the gill in some Mytilidge and in 

 Avicula. He has since found it in about thirty species. It is a 

 distinct eye with a pigmented retina and a cubicular crystalline lens. 

 Perhaps the fight comes through a translucent triangular zone near the 



* Ann. Nat. Hist., iii. (1909) pp. 111-22 (4 figs.). 



t C.R. Soc. Biol. Paris, lxvi. (1909) pp. 80-2. 



X Bull. Classe Sci. Acad. Belg., Nos. 9-10 (1908) pp. 773-9. 



