. The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . -oin an advanced stage of development. The egg of the Fifteen-spined Stickleback{Gasterosteusspinachia), hitherto regarded as the largest Teleostean egg in proportionto the size of the animal, measures only three millimetres in diameter. Besides theSiluroids of the genera Arius and Galeichthys, which have very large eggs, at leasttwo species of Tilapia were known to give shelter to their eggs in the mannernoticed above—viz., T. simonis Gthr. {Chrotiiis paterfamilias,
. The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . -oin an advanced stage of development. The egg of the Fifteen-spined Stickleback{Gasterosteusspinachia), hitherto regarded as the largest Teleostean egg in proportionto the size of the animal, measures only three millimetres in diameter. Besides theSiluroids of the genera Arius and Galeichthys, which have very large eggs, at leasttwo species of Tilapia were known to give shelter to their eggs in the mannernoticed above—viz., T. simonis Gthr. {Chrotiiis paterfamilias, Lortet), as observedby Professor Lortet in Lake Tiberias, and T. nilotica, Cuv., as noticed by me in a. 198 THE specimen, collected by Canon Tristram in the same lake. Hut these eggs, producedby fishes of the size of our common jierch, are very numerous, and measure only about2 millim in diameter. It has, besides, been observed in these 7ila/<iir, as well asin the Siluroids, that the function of protecting the eggs dev(jlves on the male sex,while, to my surprise, the Tanganyika fish proved on autopsy to be a this is constantly so, or whether either parent takes to the nursing duties,remains to be ascertained by examination of a larger number of specimens. I amall llie more disposed to think the latter possibility will be confirmed, from the factthat a specimen of Iilapia iiilolica with the pharynx filled with embryos belongsto the female sex, while Dr. Lortets observations on T. simo/iishad led to llic beliefthat specimens carrying eggs in that manner are invariably males. It is here necessary to recall the observation contained in Livingstone
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