On a Freshwater Medusa from the River Niger. 29 



developed form may also be shown to exist, — or spiders, 

 although it may be only a few species, have the power of 

 changing their skins in the adult condition, which has not 

 been observed hitherto. 



I therefore examined one or two females from my collec- 

 tion which, according to external appearances, were mature. 

 In none of them did I find an epigyne near the pulmonary 

 opercula. On the 20th of October I again examined a Filistata^ 

 which apparently died during (the last?) ecdysis. This 

 likewise had no epigyne at the usual place ; but I discovered 

 on the lower half of the ventral side of the abdomen, towards 

 the spinnerets, a horizontal suture ("Fuge"), which was 

 almost entirely covered by close-lying hairs. As I attempted 

 to introduce a needle beneath the suture, which I had no 

 difficulty in doing, the spider moved its legs (it was conse- 

 quently not yet dead), and a drop of clear viscid fluid showed 

 itself at the suture, receded again, and again issued forth 

 when I exerted a little pressure. Can this have been a mass 

 of germ-cells from the ovary? I have not examined the 

 parthenogenetic female, since it is valuable to me for further 

 observations, and I was afraid of injuring itj it is still alive 

 at the present moment (February 1893). 



VIII. — On a Medusa observed hy Dr. Tautnin in the Biver 

 Niger at bamakou {French Soudan). By M. JuLES DE 



G UEENE *. 



The Societe Zoologique is indebted to M. Gaston Tissandier 

 for the first intelligence of the interesting circumstance 

 detailed below. 



In consequence of an article, accompanied by three figures 

 and giving a resume of R. T. Glinther's paper on the Medusa 

 of Lake Tanganyika t, published by me in 'La Nature':}:, 

 the courteous editor of that journal received a letter from 

 Nouka-Hiva (Marquesas Islands), Avhich he hastened to 

 communicate to me. The letter bears the sionature of 



o 



* Translated from the ' Bulletin de la Societe Zoologique de France/ 

 t. xviii. (seance du 28 novembre, 1893) pp. 225-230 : from a separate 

 impression communicated by the Author. 



t R. T. Giinther, "Preliminary Account of the Freshwater Medusa of 

 Lake Tanganyika," Ann. & Mag. Nat. Hist. ser. 6, vol. xi. pp. 269-275, 

 pis. xiii. and xiv. 



t J. de Guerne, " La Meduse du lac Tanganyika," La Kature, June 24, 

 1893. 



