40 



at the same level as the molar expansion, rather large, terminal joint tapering' 

 to a narrow incurved point. First pair of maxillae with the masticatory 

 lobe rather large, densely hairy- and armed both at the tip and the inner 

 edge with strong denticulated spines, basal lobe small, palp normal. Second 

 pair of maxillae with the lobes rather narrow. Maxillipeds well developed, 

 masticatory lobes very large and broadly rounded at the tip, palp attenuated, 

 with the terminal joint comparatively short. Anterior gnathopoda rather 

 small and attenuated, scarcely subcheliform, propodos tapering, without any 

 distinctly defined palmar edge, dactylus short and curved, pectinate at the 

 base. Posterior gnathopoda much longer than the anterior, propodos not pro- 

 duced at the tip. The 3 posterior pairs of pereiopoda successively increasing 

 in length, last pair rather elongated. Branchial lamellae very large and com- 

 plicated, with a double series of small secondary lamellae arranged in a 

 bipinnated manner. Incubatory lamellae rather narrow but somewhat expanded 

 at the end. Last pair of uropoda rather large, rami lanceolate with the edges 

 denticulated and setous. Telson deeply cleft. 



Remark*. - The present genus, established by Costa, is chiefly charac- 

 terised by the unusual length of the antenna! flagella, by the comparatively 

 small, not subcheliform, anterior gnathopoda, and by the very complicated 

 structure of the branchial lamellae. From the genus Lysianassa, which seems 

 to be its nearest ally, it, moreover, differs by the deeply incised telson. The 

 genus would seem on the whole to have a southern range. It comprises as 

 yet only 3 species, 2 of which, /. tannin Costa and /. a- f 'finis Heller, are 

 peculiar to the Mediterranean, whereas the 3rd species, /. spinicornis Boeck, 

 besides in the Mediterranean, is also found on the coast of Norway. Two 

 other species have been described an belongning to this genus; but the one, 

 I. mi unfit* Boeck, is only founded on young specimens of I. spinicornis, and 

 the other, I. nmbo>if/t* (jr. 0. Sars, has on closer examination been found not 

 to belong to the present genus. 



6. Ichnopus splnicornis, (Boeck). 



(PI. 15). 



Ichnopus spinicornis, Boeck, Crust. Amphip. bor. & arct. p. 18. 

 Syn : Ichnopus minutus Boeck. 

 mlccnlatns. Heller. 



Body rather elongated, with the back rounded. Cephalon comparatively 

 small and having the lateral corners somewhat projecting and angular. 

 Coxal plates successively increasing in size to the 4th pair, which do not 



