196 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tion of the eye in this Amphipod. It took place in a series of definite 

 steps or stages, each of considerable magnitude. The end was an entire 

 loss of the eye-pigment, a broken irregular arrangement of the ommatidia, 

 and a great reduction in their number. The continuation of the process 

 for a few steps further may be thought of as likely to lead to the 

 complete absence of eyes seen in Amphipod genera from subterranean 

 waters. The changes all took place in exact conformity with Mendel's 

 Law. The mutation from black to red pigment arose only once in the 

 course of the work ; the complete loss of the inter-retinal coloured 

 pigment occurred four times in one family of 733, and never again ; the 

 loss of the white, extra-retinal pigment originated on several occasions 

 and in apparent independence. The experiments give striking illustra- 

 tions of the way in which the offspring of two abnormal parents may be 

 quite normal in their characters, and yet transmit the abnormalities. 



Malacostraca of Natal* — T. R. R. Stebbing reports on the higher 

 Crustaceans of Natal, and deals especially with Platylamhrus quemvis 

 sp. u., Atergates fioridus (Linn.), Macrophthalmus grandidieri A. Milne- 

 Edwards, Ura lacteus de Haan, Dotilla clepsydra sp. n., and Rhyncho- 

 cinetes typus Milne-Edwards. 



Morphology of Bathynella.f — W. T. Caiman discusses some of the 

 structural peculiarities of Bathynella nutans, one of the most remarkable 

 of living Crustacea. It is undoubtedly a degenerate member of the 

 Syncarida, a group of Crustacea which has persisted from Carboniferous 

 times, and of which the only other living representatives are found in 

 Australia and Tasmania. It was found in 1882 in a well in Prague ; it 

 has been recently rediscovered in Switzerland. In some features, such 

 as the absence of eyes, it shows degeneracy, which may be correlated 

 with life in subterranean waters, though mere minuteness of size may 

 also be a factor. The division Syncarida, and the order Anaspidacea 

 include five families : — Anaspidse, Koonungidge, Acanthotelsonida3, 

 Bathynellidte, and Uronectidse. The Syncarida form by themselves a 

 division of equal rank with the Eucarida and Peracarida, but allied 

 more closely with the former than with the latter. 



Body-colour and Blood-colour in Amphipods.J — John Tait finds 

 that some of the Gammaridea owe their body-colour in a large degree to 

 the colour of their blood. In Isopods this is the case to a much less 

 degree. A dark green Gammarus has greenish blood plasma, a slate- 

 grey specimen bluish plasma, a brown has brown, while a brownish-red 

 has violet plasma. Pale yellow and white specimens of Gammarus have 

 plasma that is almost colourless, while the blood of some of them, 

 viewed in bulk, is actually milk-white. Specimens of OrchesUa in which 

 a blue tint is visible have bright blue plasma ; those in which no blue is 

 to be seen, yellow-brown specimens, have yellow plasma. The external 

 covering of these shore Amphipods being devoid of chromatophores, and 



* Ann. Durban Museum, ii. (1917) pp. 1-33 (6 pis.). 



t Quart. Journ. Micr. Sci., Ixii. (1917) pp. 489-514 (14 figs.). 



: Proc. Roy. Phys. Soc, xx. (1917) pp. 159-63. 



