ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581 



is imbedded in connective tissue, so deeply indeed as almost to 

 preclude the idea of its being affected by light. In a postscript 

 Mr. Spencer adds that he has since found the eye in Iguana, Chameleo 

 vulgaris, and Lacerta ocellata, and has traced the nerve into the 

 proximal part of the epiphysis. 



Probable Cause of some Monstrosities.* — Dr. E. Cutler suggests 

 that abnormal forms of spermatozoa are sometimes the cause of 

 teratologieal conditions in the children, and states that abnormal 

 forms of the following character have been observed in the sperm of 

 man : spermatozoa with two or three bodies, with one body and two 

 or three tails, with two bodies and two tails, and two bodies and three 

 tails. The average proportion of these monstrous spermatozoa is 

 almost 1 in 50,000 ; their movements are slower, but more vigorous 

 than those of normal forms. In examining the urine for abnormal 

 spermatozoa, it is advisable to make use of a cell 2^ by 3/4 by 1/16 

 inch, and a dry 1/4 inch objective with a long working distance. 



Origin of the Deep-sea Fauna in the Sub-alpine Lakes.f — Three 

 explanations have been offered of the origin and ancestors of the deep- 

 sea fauna of these lakes : according to Prof. A. Forel only one is of 

 practical value. The theory that this fauna is derived from old deep- 

 sea fauna of the tertiary period is inadmissible, for the glacial epoch 

 would have destroyed that fauna, although, it is true, certain organisms, 

 e. g. Desoria glacialis, the ice flea, and Protococcus nivalis, flourish in 

 ice ; moreover, the existing fauna is of quaternary origin. The sur- 

 rounding mountains, which stood above the covering of ice, may have 

 supported life, but this would have nothing in common with the deep- 

 lake fauna. 



According to the author, this fauna arose partly from voluntary 

 and partly from involuntary migration from lake to lake. When the 

 glacial period ended, as the ice gradually retreated up the valleys, 

 animals and plants, which had been driven into neighbouring regions, 

 would wander back ; but this would only apply to river or land fauna, 

 since deep-lake fauna require special adaptations. The pelagic fauna 

 might arise by small littoral animals being carried by currents to the 

 centre of the lake, and there, by natural selection, their descendants might 

 become transparent and otherwise modified for a pelagic existence. 



But the bottoms of lakes are completely separated from one another ; 

 and even to rise to the surface would be impossible to most of the 

 animals adapted to a deep-lake existence. According to Forel 

 the only explanation is that this particular fauna is derived from the 

 littoral fauna, since a large number of species is found to be common 

 to both fauna, and some are common to the cave fauna. By a voluntary 

 migration it is supposed that littoral animals have wandered from the 

 shore, have become bewildered, and in their efforts to return, got 

 further and further from the shore, and therefore in deeper and deeper 

 water ; they thus lose their way, and have to remain where they are ; 

 their eyes are of little use to them, since for sight they require a 

 bright light, which is, of course, absent in the depths. 



* Medical World, iv. (1886) pp. 18-20. 



t N. Denk. Schweizer. Gesell. f. d. Ges. Naturwiss., xxix. (1SS5) 234 pp. 

 Cf. Naturfoidcker, xix. (1886) pp. 191-3. 



