380 



the basal joint rather large, and produced at the infero-lateral corners to a 

 sharp point, at some distance from which, there is, on the lower side, a small 

 dentiform projection. Last pair of uropoda with the inner ramus considerably 

 longer than the outer. Telson nearly as in I. obesa. Body very variable 

 in colour, now banded transversely in the same manner as in I. obesa, now 

 variegated with larger dark brownish shadows, sometimes very darkly colou- 

 red all over, nearly black. Length of adult female scarcely exceeding 5mm. 



Remarks. Though very like the type species as to external ap- 

 pearance, this form may, on a closer examination, be readily distinguished, 

 not only by its much inferior size, and different colouring, but also by several 

 well-marked structural details, the most conspicuous of which is the very 

 different form of the last pair of epimeral plates of metasome. As shown 

 by the above diagnosis and the appended figures, there are even to be found 

 in the structure of the oral parts some very striking differences from the 

 same parts in the type species. The form recorded by the Rev. Mr. Stebbing 

 as 1. eblunce var. is undoubtedly identical with the species here treated of, 

 and very different from the true I. eblance of Sp. Bate. 



Occurrence. I have met with this species not infrequently both off 

 the south and west coasts of Norway, in comparatively shallow water among 

 algse, especially on rocky bottom, sloping steeply from the shore. 



Distribution. British Isles (Stebbing), Mediterranean at Spezia cnid 

 Messina (the author). 



Gen. 3. Odius, Lilljeborg, 1865. 

 Syn. : Otus, Sp. Bate. 



Body highly compressed and keeled dorsally, with the integuments 

 strongly incrusted. Cephalon produced in front to a deflexed rostrum, and 

 having the lateral corners well developed. Coxal plates rather large, 4th pair 

 having the outer part considerably expanded, and truncated at the tip. Eyes 

 distinct. Antennae very short. Anterior lip extremely narrow, and minutely 

 bifid at the tip; posterior lip with the lobes acutely produced. Mandibles 

 very slender, with the cutting part greatly prolonged, and acuminate at the 

 tip, molar expansion distinct, though extremely small, palp slender and nearly 

 naked. First pair of maxillae with the masticatory lobe much elongated and 

 tapering to an acute point, basal lobe comparatively small and narrow, palp 

 quite rudimentary, only consisting of a single conical joint. Second pair 

 of maxillae with both lobes rather narrow and obliquely truncated at the tip. 



