536 



where, in some places, it is rather abundant, for instance at Bejan, in the 



outer part of that fjord. 



Distribution. Arctic Ocean: Greenland (Hansen), Spitsbergen (Goes), 



Bohuslan (Malm). 



Gen 12- Idunella, G. 0, Sars, n. 



Form of body about as in Lilljeboryia. Urosome without any dorsal 

 projections. Eyes imperfectly developed. Antennae subequal in length, the 

 superior ones with a well-developed accessory appendage. Oral parts 

 resembling those in LiUjeborgia, except that the mandibular palps are much 

 more fully developed, with the terminal joint elongated and falciform, and 

 that the palps of the maxillipeds are smaller. Gnathopoda in female subequal, 

 with the carpus but slightly produced below, and the propodos much expanded 

 distally, dactylus smooth. Anterior gnathopoda in male much larger than 

 the posterior, and peculiarly modified, being conspicuously forcipate, with 

 the palm of the propodos deeply concave, and produced below to an acute 

 projection, against which the strongly curved dactylus impinges when closed. 

 Pereiopoda nearly as in LiUjeborgia. Last pair of uropoda with the outer 

 ramus distinctly biarticulate. Telson rather large and deeply cleft. 



Remarks. This new genus is founded upon the form described at 

 an earlier date by the author as LiUjeborgia (eqvicornis. On a closer examina- 

 tion of this form, I have found it to differ in several points so very markedly 

 from the other species of Lilljeborgia, as more properly to be regarded as the 

 type of a separate, though closely allied genus, for which I have proposed the 

 above name, being the diminutive form of Iduna. Besides in the subequal 

 antennae, and in the remarkable structure of the gnathopoda in the two sexes, 

 it differs in the much fuller development of the mandibular palps, whereas 

 the palps of the maxillipeds are not nearly so strong as in the genus 

 f.il/jclinrt/nr. it further differs in the outer ramus of the last pair of uropoda 

 being distinctly biarticulate. The genus comprises as yet but a single species, 

 to be described below. 



