-626 " THETIS " SCIENTIFIC RESULTS. 



Dana's statements that the feet are a]l vergiform and that the 

 first and second peraeopods, though a little stouter than the 

 gnathopods, are still slender, are irreconcilable with the 

 undoubtedly subchelate character of those peraeopods in 

 Haswell's /. punctatus. 



As will be presently explained, in " Das Tierreich " I have 

 .misdescribed the third uropod. The generic account should 

 state that the outer ramus of this appendage is of variable length, 

 sometimes longer than the peduncle. 



ICILIUS DAN^, Stehhing. 



Icilius dante, Stebbing, Chall. Rep., Zool., xxix,, 1888, p. 1203, 

 pi. cxxxiii. 



(Plate lix.A.) 



Stations 28, 57. 



Almost all the specimens of this and the congeneric forms 

 proved to be females as attested by their possession in common 

 of very ample marsupial plates. In the present form eggs few 

 and large were occasionally present. As already noticed, this 

 species stands alone in having the hind margin of the seventh 

 peraeon segment acutely produced at the middle. It differs from 

 the other two Australian forms in a similar production of the 

 first and second pleon segments, which are also laterally carinate, 

 but agrees with I. pv,nctatus in having the postero-lateral angles 

 of those segments only minutely out-drawn. In all three forms 

 the seventh is the longest of the peraeon segments, and the first 

 is the longest of the pleon .segments, with the exception, of the 

 fourth, which, however, when the tail is flattened out, is to a 

 considerable extent concealed. 



The mouth-organs and gnathopods apparently are in very close 

 agreement in all the Australian forms. The peraeopods by their 

 comparative slenderness contrast in this species with those of 

 the other two forms, but so does the general build of the species 

 itself, and some may argue that though sexually reproductive, 

 these specimens are morphologically immature. The combination 

 of characters does not make this very probable. In the fifth 

 peraeopod the second joint evenly sinuous, convex above, concave 

 below, ending in an acute tooth, descending below the adjoining 

 tooth of the lower margin ; the fourth joint is quite slender, com- 

 pared with that joint in the other two forms. 



The pleopods are very distinctive. In those of the first pair 

 the peduncle is more than twice as long as bi'oad, with parallel 

 margins. 



The uropods are slender, the peduncle in the first pair longer 

 than the rami, of which the outer is shorter than the inner ; the 



