660 • MRS. E. W. SEXTON OS 



"Moorflether Concave. Obevflaclie II. .23.vii.00." 11 speci- 

 mens; the largest, males, measured 10-11 mm.; all the brackish- 

 wa.ter form. 



"Moorflether Concave. 23.viii.00." 129 specimens: largest 

 15 mm. Freshwater, brackish, and "intermediate" forms, and 

 one specimen of the exceedingly narrow, thread-like form described 

 from the Grasbrookhafen sample. 



" Moorflether Concave. Ponton. 23.viii.00." 5 specimens, the 

 largest, a male of 14 mm., shows the freshwater characters ; the 

 others are of the brackish-water type. 



" Moorflether Concave. 24.ix.00." 37 specimens, brackish- 

 water form, largest 12 mm. 



The three following samples are all unmistakable brackish- 

 water form. The " Prielen " are little channels cut in the banks 

 of the river ; the current is less strong, and the growth of vege- 

 tation and animal life richer than in the Elbe. 



" Dove Elbe. Oberfl. 2.vii.00," 6 specimens, lai-gest about 

 8 mm. 



"I. P. r. 0. 7.vi.00 " ( = Kechtsseitiger Elbpriel am Spaden- 

 land, Oberflache). 6 specimens, largest 10 mm. 



" I. P. r. O. 2.vii.00." 14 specimens, largest 8 mm. 



The remaining samples are all fine examples of the typical 

 freshwater form. . 



"Kaltenhofe. ' Wasserprobe aus Filter No. 16 entnommen 

 am 6. Dec. 1894.' " .3 specimens, the largest 22 mm. 



" Hamburger Wasserleitung." 5 specimens, 18-20 mm. long. 



" Hambiu^ger Wasserleitung. Samuelson." 71 specimens. 

 Dr. Kraepelin has given a very interesting account of the condi- 

 tions of animal life in the miderground " Wasserleitung " of Ham- 

 bui'g, conditions much more favourable than in the Elbe, owing 

 to the greater abundance of food, the protection from many 

 enemies, and the lesser temperature variations. He mentions 

 this species under the name of G. pulex as second only in numbers 

 to Asellus aquaticus among the Edriophthalma met with in the 

 series of samples taken. 



5. Bremerhaven : Herr Klie. One tube " Alter Haf en. x.ll." 

 10 specimens, the largest a female 9 mm., from which several of 

 the figures are drawn. This sample contains one of the thread- 

 like form described above. These Bremerhaven specimens, which 

 come from Salter water than the preceding, have scarcely any of 

 the long fine hairs developed, which so strikingly characterise the 

 freshwater animals. 



6. Irish Lakes : British Museum (coll. by Major Trevel3'an). 

 "Lough Nadarragh." 4 large specimens, male and female, 



about 18 mm. in length. Freshwater form, exactly like those 

 from the Hamburg Wasserleitung. 



" Lough Keenaghan." 2 specimens, male and female G. pulex. 



" Lough Keenaghan." 1 specimen, a female, freshwater form, 

 G . zaddacM. . 



