some Freshwater AmpJn'porls. 243 



(22) Vejdovsky, F. " Ueber einige Siisswasseraniphipoden. II. Zur 

 Frage der Aiigenrudimente von JViphart/tis," ibid. 1900. 



(23) ViSMEs Kaxr, AV. F. de. " Xiphaiyiift Kochianus, Bate, in an 

 Irish Lake, and N. suhterraneus, Leach, in Kent," Ann. & M;ig. 

 Nat. Hist. ser. 7, vol. xiv, 1904, pp. 274-283, pi. viii. 



(24) Wbzksniowski, August. " O trzech kielziich podziemnych. De 



tribus Crustaceis Amphipod. subterraueis," Pani. fvziogT. viii. 

 1888. 



(25) . " T^eber drei nnterird. Gammariden,'' Z. f. w. Z. B. -OO, 



pp. 600-725, 1890, Taf. xxviii.-xxxii. 



EXPLANATION OF THE PLATES. 

 General siynificance of the letters. 



e. Cuticle. 

 dh. Ordinary setfe. 

 hk. Hyaline spheres iu the crystal- 

 line cones. 

 hp. Hypodermis. 

 />:)•. Crystalline cones. 



n. Secondary branch of tlie 



lii'.>t anteuufe. 

 ly. Pigment-cells. 

 r. Petinula-cells. 

 sp. Sensory brushes. 

 s/>o, spo'. Segmental cuticular 

 seuse-oro'ans. 



Plate XI. 



Fiy. 1. ^af/!»/o«^J"r7e f7s?«es2 under low magnification. The appendages 

 of the left side only are shown. 



Fiy. 2. Portion of the third joint of the upper (first) antennaj, with the 

 accessory branch (71). 



Fiij. 3. Terminal portion of the antenna, with two hyaline clubs [so- 

 called olfactory clubs] and a sensory brush. 



Fiy. 4. Mandible, left side, from below. 



Fiy. 5. Maxilla of first pair ; the inner lobe is not visible in this position. 



Fiy. G. a, inner, h, outer teeth of the middle lobe of maxilla of first 

 pair. 



Fiy. 7. Maxilla of the second pair. 



Fiy. 8. Maxillipede of the left side. 



Fiys. 9-11. Gnathopods of the fir.st (a) and second (It) pairs of three indi- 

 viduals under nearly equal magnification, iu order to show the 

 moderate variability of their form. 



Fiy. 12. Uropod of the third pair. 



Fiy. 13. Telson from above, in order to show the position of the sensory 

 brushes. 



Fiy. 14. Outer (c) and fibrous (c') cuticle, in which the urn of a sensory 

 brush is embedded, ne, nerve-ending. 



Fiy. 15. Double hooks of the first and second pleopods. 



Plate XII. 



Fiy. 16. Distribution of the crystalline cones in the pigment and on its 



peiiphery under low magnification. Bathyrmyx. 

 Fiy. 17. Head from the left side, with basal joints of the first and second 



antennai, the dilFuse eye, and the segmental cuticular senso- 



organs. Highly magnified. 

 Fiy. 18. Head of the sanie animal seen from the right side, in order to 



rihow the variable number of crystalline cones. 



