ON LIVING MALAPTERURUS. 375 



West Africa is a new species. I refer to his 1 paper for the zoo- 

 logical characteristics, which at first sight and with less complete 

 comparison, had led to this suggestion. 



Our specimens were all small, without barbels, between 1 2-5 and 

 37*5 cm. long, whilst Bilharz measured one of 32" =57-5 cm. 

 The quick growth of one which was kept alive longest, seems to 

 show that the creatures were still young. Most of them were 

 females. 



It is impossible to form a good idea of Malapterurus from 

 specimens in spirits of wine and from drawings taken from them. 

 In drawings, the position in which the barbels are held is par- 

 ticularly incorrect, as they are represented as hanging down in a 

 flabby manner and curled, whilst in the healthy fish they are 

 extended in straight lines and far apart (see Figs. 10, n). 



Another characteristic in the appearance of the Malapterurus, 

 which is no longer recognisable in specimens in spirits of wine, 

 consists of beautiful, regular, broad transverse folds, which in our 

 fish were always $-8 mm. in size (unquestionably more in larger 

 fish), and which show themselves on the concave side of the fish 

 when it bends laterally. They are made by the organ which 

 envelops the fish in the form of a thick walled tube, the outer 

 layers of which arrange themselves in folds over the contracted 

 muscles of the flanks, whereas in other fish, the thin and firmly 

 attached skin always follows exactly the contour of the body. 



In life, the organ as well as the skin covering it, is transparent, 

 so that in the light one looks into its reddish depth. In death, 

 especially in specimens in spirits, it is dim and opaque. The 

 general colour of such specimens is gray ; in life, our fish were 

 brown except the black spots with which they were, as it were, 

 sprinkled on the back ; the weaker ones were yellowish brown, the 

 stronger ones were rather deep red brown. The colour even of the 

 same fish varied. In the dark they became blackish, under the 

 effect of light, bright again. When fatigued by experiments they 

 looked pale, after resting for a few days they appeared again deeper 

 coloured. 



The animals usually remained motionless in the darkest part of 

 the bottom of the tank with barbels far extended. At night 

 they seem to become more lively ; at least in Creek Town, fishes 

 which were kept in readiness to be shipped off, perished through 

 jumping out of their vessels during the night. When the fish had 

 fresh water given to them in the tubs in which I originally kept 



