539 



make a satisfactorily distinct definition of these 3 groups separately, I have 

 preferred to combine them in one family, whicli may more properly be named after 

 the genus first established, viz, that oiFhoHs Kroyer. It is cjiiefly distinguished 

 from the Gammaridcs by the structure of tlie last pair of uropoda, and that 

 of the telson, which latter exhibits a more or less distinct tul)ular shape, on 

 account of its receiving within it the terminal part of the intestine. Some of 

 the forms pertaining to tliis family are stated to construct al)odcs in wliicli 

 tliey take shelter, tlius approaching in tiiciv habits the true domicolons 

 forms belonging to the 2 succeeding families. Tlic ])resent family comprises 

 10 Norweffian genera. 



Gen. 1. MicrodeutopUS, Costa, 1853. 



Syn: I.Pmbos, Sp. Bate. 



» Autoiioe, Bruzelius (pavtj. 



Body slender and but little compressed, with the coxal plates compa- 

 ratively small, 1st pair produced in front, especially in the male, 4th pair 

 not emargiuated posteriorly. Epiraeral plates of metasome comparatively 

 small, and scarcelj' produced at the lateral corners. Eyes di.stinct, though 

 ratlier small. Superior antennae much longer than tlie inferior, and provided 

 with a distinct accessory appendage. Anterior lip rounded ; po.sterior lip 

 ratlier large, with distinctly developed inner lobes, outer lobes pi'oduced laterall}^ 

 to an acuminate lappet. Mandibles strong, with the palp of moderate size 

 and having the terminal joint attenuated. Fii'st pair of maxilli3B with the 

 basal lobe small, unisetose; 2nd pair with the lobes rounded. Maxillipeds 

 with both the basal and masticatory lobes well developed, palp not veiy 

 large, (irnathopoda in female comparatively small, the anterior ones being 

 a little larger than the posterior, and having tlie propodos imperfectly 

 subcheliform ; propodos of the po.sterior ones rather narrow, with the ]ialm 

 nearly transverse, and very .short. Anterior gnathopoda in male greatly 

 developed, with the carpus extremely large and swollen, lieing more or less 

 produced in front, so as to form together with the propodos and dactylus a 

 kind of chela. The 2 anterior pairs of pereiopoda of moderate size, and 

 exactly alike; the 3 posterior pairs rapidly increasing in length, and having 

 the basal joint but little expanded. Branchial lamellse simple ; incubatory 

 lamellae large and broad. Last pair of uropoda not extending beyond tiie 

 others, basal part somewhat dilated inferiorlj', rami sublinear, and sparsely 



