368 Mr. P. W. Bassett-Smith on 



Dichelesthiina. 

 PSEUDOCYCNUS, Heller. 



Pseudocycnus append icahit us } Hell. 



Ten specimens of lliis rare animal were found attached to 

 the gills of Thynnus macropterus at Aden ; they were all 

 mature females. These I kept alive for some time. The 

 vascular system is very elaborate, and apparently these animals, 

 like those of the genus Lernanthropus, are essentially " blood- 

 suckers," being full of red blood. The specimens originally 

 described by Heller * were taken in the Indian Ocean on a 

 species of u Coryphoena" with which these agree in almost 

 every detail, except that in my specimens stump-like rudi- 

 ments of the fifth pair of limbs carrying a single small hair 

 were present at the extreme end of the genital segment on 

 either side just in front of the flap-like processes which protect 

 the ovarian openings. 



Length 10 millim. 



Lernantiikopus, Nordm. 



LernantJiropus ?uidus, sp. n. (PI. XII. figs. 2, 3, 4.) 



While at Aden I was astonished by the great number of 

 specimens of an animal of this genus which were present 

 attached to the gills of a large grey mullet (Mugil } sp.) very 

 common in the market. Scarcely a fish would be examined 

 without finding many specimens ; as they attached themselves 

 very firmly, they were not easily washed away. It seems to 

 be a genus widely distributed, and I have taken out here a 

 good many species. This one appears to be very remarkable. 

 Obtaining them fresh and in large numbers, one was able to 

 keep specimens alive for some time, when their brilliant red 

 colouring and movements made them very interesting to 

 watch, as described by Hesse. Both males and females w T ere 

 found separately, and also once " in copula," as shown in the 

 figure ; the males are much smaller than the females, but did 

 not show the more brilliant colouring, as in Hesse's plates; 

 the free-swimming embryos were taken from a watch-glass 

 about twelve hours after the eggs were discharged. The 

 chief characteristics of this species are the entirely exposed 

 condition of the abdomen and the great length of the processes 

 representing the fourth pair of limbs. 



* ' Reise der Fregatte No vara,' pp. 218-219. 



