I '08. 167 



from this onwards to the apex the margins are clothed with 

 long setae. The apex is rounded with a minute central point 

 and a blunt spine marking each outer angle ; it bears eight 

 long setae and a few short hairs. 



The eye (fig. 3) is short ; the corneal area is indistinctly 

 marked off from the stalk ; it only shows the very faintest traces 

 of facets, and is entirely devoid of black pigment. The stalk 

 is considerably wider than the cornea and bears seven strong 

 spines, two on the outer side and five on the inner superior 

 aspect. 



The antennular peduncle reaches about to the apex of the 

 rostrum. The proximal joint is much longer than the tw^o 

 following combined ; it bears at its base a short forwardly 

 directed lateral process. The second joint is almost twice the 

 length of the third and is furnished with three spines, two on 

 the inner and one on the outer aspect. In the female the 

 flagella are very long and of about equal thickness ; the outer 

 and low^er ramus is the longer. The basal joints of the an- 

 tennae are spinose below. The antennal scale (fig. 2) reaches 

 beyond the rostrum by almost one-half its length and is almost 

 three and a half times as long as wide. The outer edge is 

 strongly concave and bears from tw^o to five teeth ^ in addition 

 to that which forms its distal termination. The lamellar por- 

 tion is narrowed anteriorly and slopes aw^ay rather rapidly from 

 the apical spine. The flagellum is much longer than the en- 

 tire length of the animal. 



The mandibles (fig. 4) bear a curved three-jointed palp ; the 

 incisor and molar processes are only separated from one an- 

 other by a groove. The characters of the tw^o pairs of maxillae 

 and the first two maxillipedes are shown in figs. 6-8. The 

 third maxillipedes are seven-jointed, and when stretched for- 

 wards reach beyond the middle of the antennal scale. The 

 exopod is long, reaching beyond the distal end of the ischium, 

 and the merus is provided with a double row of spines on its 

 outer and inferior aspect. All the joints are strongly setose 

 ventrally. 



The first three pairs of pereiopods are chelate, the third pair 

 being very much the longest. The first pair reaches slightly 

 beyond the apex of the antennal scale ; the carpus is a little 

 longer than the merus and the chela is about three-fifths the 

 length of the carpus. The second pair reaches beyond the an- 

 tennal scale by the whole chela and nearly one-third of the 

 carpus ; the merus is three-quarters the length of the ischium 

 and the chela is half as long again as that of the first pair. 

 The legs of the third pair are equal and symmetrical (thus 

 sharply contrasting with R. spongicola, Alcock and Anderson, 

 in which one is immensely bigger than the other) ; they are 

 stouter .than any of the others and reach beyond the antennal 

 scale by the chela and four-fifths of the carpus. The merus 

 is only slightly longer than the carpus and the large chela is 



1 Milne-Edwards (1883) does not figure any spines on the outer margin 

 of the antennal scale. Although these are present in all^ three Irish 

 examples, it is quite possible that they are sometimes missing. 



