38 SUMMARY OK CURRENT RESEARCHES RELATING TO 



taste of some fresh- water fishes from certain basins is due to the animals 

 becoming saturated with " the essence of Oscillarias," on which they 

 directly or indirectly feed. The bad taste is most marked in the skin- 

 glands and the kidneys, and is less marked, of course, in proportion as 

 the fish is less vegetarian in its diet. 



Scales of Fishes.* — T. D. A. Cockered describes the structure of 

 the scales of some African Characinid fishes, which are primitive relatives 

 of the Cyprinidse. The sculpture of an ordinary fish-scale includes two 

 important elements, the circuli and the radii. The circuli are circular 

 lines, sometimes referred to as " lines of growth," while the radii are 

 lines or grooves radiating outward from the nuclear area, The radii 

 seem to be of secondary origin. They may lose their radial arrange- 

 ment and simulate circuli, just as circuli may become transverse. The 

 African Characinidae have scales of two main types — one Cyprinoid 

 (including Hydrocyoninas and Citharininae), the other Ctenoid (including 

 Ichthyoborinae and Distichodontinaa). In another paper, f the author 

 describes the scales of Morniyrid fishes, which are cycloid, with well- 

 developed circuli and with strong basal radii, but with this remarkable 

 feature, that the apical radii are greatly modified and join irregularly, 

 forming a network. 



t3 



Variations in Ureters of Weever.J — J. Chaine finds that in this 

 fish (Trachi)ius draco) the commonest arrangement of the ureters is that 

 they unite just behind the posterior end of the kidney, forming a 

 relatively long common canal to the bladder. In many cases they do 

 not unite till near the bladder. In rare cases (two were observed) they 

 open separately into the bladder. 



Variation of Species of Notropis.§ — H. W. Fowler shows the range 

 of variation in the important or fundamental characters of a majority of 

 the species of this genus of Cyprinidaa. 



Growth of Salmo hucho.|j — 0. Haempel finds that the methods of 

 estimating age in various Teleosteans apply well to Salmo hucho, where 

 the winter and summer zones can be read in the scales, otoliths, oper- 

 culum, vertebrae, and upper jaw-. The rings on the vertebras are 

 particularly clear. In the first four years there is great increase in 

 length, about 15 cm. annually, but it then sinks to 2-5 cm. annually. 

 On the other hand, the increase in weight is at first slight (250 grm. in 

 a year), but from the fifth year onwards, 1-2 kilogrm. per annum. 



Biological Stations. 1f — Chancey Juday gives an interesting illus- 

 trated account of some of the European biological stations — at Plymouth, 

 Port Erin, Cullercoats, Sutton Broad, Millport, St. Andrews, Bergen, 

 Kristineberg, Furesee, Helder, Overmeire, Heligoland, Plon, Roscoff, 



* Smithsonian Misc. Coll., lvi. (1910) No. 1, pp. 1-10 (2 pis. and 2 figs.). 

 + Tom. cit., No. 3, pp. 1-4 (3 figs.). 

 X P.V. Soc. Sci. Bordeaux, 1909, pp. 5-6. 



§ Proc. Acad. Nat. Sci. Philadelphia, 1910, pp. 273-93 (7 pis.). 

 || Internat. Rev. Hydrobiol., iii. (1910) pp. 136-55. See also Zool. Zentralbl. 

 xvii. (1910) p. 686. 



^ Trans. Wisconsin Acad., xvi. (1910) pp. 1257-77 (4 pis.). 



