&3 



only the anterior half of tlie lateral margins, in the second and 

 third segments the middle portion of the lateral margins, in the 

 fifth and sixth segments they reach nearly, and in the seventh 

 •cgment quite, to the pos'tero-lateral angles." 



His description was taken from the type in the Paris 

 Museum, " an adult male," 40 mm. long. It agrees 

 well with our specimen, which appears to be a female, 

 being without the male appendages on the seventh 

 peraeon segment and the second pleopods. The side- 

 plates are obviously quite different from those of the male 

 i. cmarginata, but they also differ very considerably from those 

 of the temale of that species^ which bars (Crustacea of Norway, 

 vol. 2_, p- 85, pi- 35, fig. 2) describes and figures as ''rather small 

 and not contiguous," It is important to remember the striking 

 dissimilarity between the side-plates in the two sexes of the 

 species in question, although I find that at least sometimes they 

 may be contiguous in the female as well as in the much larger 

 male, whereas in Idotca iiidica there is no approach to contiguity,. 

 the whole series being well separated. 



Miers gives the flagellum of the second antennae as eighteen- 

 jointed, and states that the last pcraeopods have "their penulti- 

 mate joints thickened and considerably elongated-" In his 

 figure this is a very notable feature, ancl may be a characteristic 

 of the adult male. In our specimen the flagellum of the second 

 antennae has on one of the pair fifteen and on the other sixteen 

 joints; the last pergeopods are not very strikingly larger than the 

 penultimate pair. 



The mouth-organs are in near general agreement in most 

 respects with those of the type species of Idotea, the /• balthka 

 (Pallas)^ as recently figured by Sars- In both species it seems to 

 me that the upper lip has a small emargination which Sars does 

 not indicate, and that the lobes of the lower lip are more squared 

 than in his figure. In both species the inner plate of the first 

 maxillae carries at the apex three phmiose setse, but its shape is 

 notquitethesameas both, the widening being near its junction 

 with the stem in 7. balfliica, but higher up in /. iiidica. The most 

 notable difference is in the maxillipeds, for these in I. balthka 

 have thepalp very distinctly four- jointed,whereas in /./W/^rt the 

 dividing line between it> second and third joints is only faintly 

 discernible, except at the edges, nor does our specimen show any 

 trace of the notch near the apex of the fourth joint, which at least 

 sometimes in /• balthica marks the place at which a small fifth 

 joint is lost in coalescence with the fourth. The epipod is oval, 

 'i he outer apex of the second joint of the stem carries four setae, 

 its process is armed with one hooked spine. 

 Length, 27 mm. 



Locality : — Hout Bay, from a depth of 9 to 20 fathoms, on 

 fine sand and broken shells. 



