34 CRUSTACEA MALACOSTRACA. III. 



other genera have been discovered in other seas, especially at Kerguelen and in the Antarctic Ocean, 

 so that the group, which answers to three families in Vanhoffen's work (1914), in the future may be 

 divided in a satisfactory way, when those southern forms have been more closely investigated. 



Kroyer. 



The best information on this difficult genus is found in Sars' "Account"; he pointed out the 

 generic characters and described 5 Norwegian species. Some few corrections and additions to the 

 northern fauna have since been published by myself (1910) and Stappers (1911). In the present paper 

 7 species from the "Ingolf" area are mentioned, 3 of which are figured in Sars' work, and 2 are new 

 to science. 



The species of Munna are far from easy to deal with, as most of them show considerable in- 

 dividual variation, and many of the specimens are very mutilated. Variations in armature with spines, 

 in the number of joints in the antennular flagella, etc., are pointed out in the descriptions of, or remarks 

 on, several species on the following pages. An important specific character not mentioned by Sars is 

 the shape of the median lamella of the male operculum; in reality the shape of this lamella, especially 

 its terminal part, affords, perhaps, the sharpest and most reliable character. Besides it may be pointed 

 out that the coxae, first joint of the thoracic legs, are thick and developed as a kind of epimera which 

 are attached to the lateral end of the segments (PI. Ill, figs. 7 b and 7 d) and, especially on the posterior 

 pairs, not always easy to discern from the segments; these coxae or epimera -- generally wanting at 

 first segment - - are frequently adorned with a tooth or with spines or processes, and sometimes the 

 lateral margins of the segments are, besides, armed in a similar way. 



Sars' diagnosis of the genus must be altered a little. As M. acanthi/era n. sp. (and M. truncata 

 Richardson) are completely without visual organs, the statement of Sars : "Eyes distinct ..." cannot be 

 maintained. As to the first pair of legs a couple of lines in his diagnosis are not quite correct, as in 

 most species there is no appreciable sexual difference in these legs. Finally it may be added that the 

 female operculum has the posterior end rounded ; in most species it is furnished with some spines on 

 the proximal half of its ventral surface. 



17. Munna Boeckii Kroyer. 

 (PI. Ill, figs, i a- 1 b). 



1839. Mnnna Boechii Kroyer, Naturh. Tidsskr. Vol. II, p. 612; PI. VI, figs. 1 9. 

 ! 1897. G. O. Sars, Account, II, p. 107; PI. 44. 



According to Sars, the antennulse have 6 joints in the flagellum, and four of these joints are long; 

 I have the same number in one of two Norwegian specimens, but only three long and two short joints in 

 the other specimen, and the specimens from the Faeroes have only the last-named number. - - The coxae 

 of second to seventh pairs of thoracic legs are armed with spines not mentioned or figured by Sars; 

 the greatest number of spines observed is two on second and seventh, three on third and fourth, and 



