74 



be distinguished. Lastly, Hansen (1908) comes to the conclusion 

 that M. tenuimana is a distinct species, but regards M. bamffica 

 and M. rugosa as synonyms. 



After examining carefully all the specimens of Munida taken 

 by the Helga, I have come to the conclusion that Hansen's 

 view of the species is the correct one. The specimens of M. 

 tenuimana are at once separable from the rest by well-marked 

 characteristics, but it is impossible to divide the others into 

 M. bamffica and M. rugosa. 



AppeUof gives the following characters as distinguishing 

 marks between M. bamffica ( =Rondeletii) and M. rugosa. 



M. bamffica. M. rugosa. 



(a) Eye-bulb hardly broader (a) Eye-bulb distinctly 

 than the stalk. broader than the stalk. 



(b) Circlet of hairs more or {b) At least a few hairs ex- 

 less rudim.entary. tend far out on corneal surface. 



(c) Hind margin of the cara- {c) Hind margin of carapace 

 pace has one or two pairs of normally has spines both at 

 spines at the sides, the central sides and in the centre. 



part being quite unarmed. 



(d) Fourth abdominal seg- (d) Fourth abdominal seg- 

 ment always without dorsal ment with two dorsal spines, 

 spines. 



Some of the Irish specimens agree with nearly all the charac- 

 ters of M. bamffica given above, and some with those of M. rugosa, 

 but between these there are individuals in which the characters 

 of both are combined. For instance, two specimens from station 

 S. R. 196 agree with M. rugosa in regard to the eye and the 

 fringe of hairs round it, yet the hind margin of the carapace 

 is practically devoid of spines, having merely a hint of one at 

 each side, and there are no spines on the fourth abdominal 

 segment. Appellof admits that in young specimens of M. rugosa 

 of less than 15 mm. these last spines may not be developed, 

 but the Irish specimen is much larger than this, measuring 

 27 mm. 



Of the ten adult specimens taken by the Helga, those from 

 stations S. R. 194, S. R. 215, and S. R. 185 agree with Appellof's 

 characters of M. rugosa as regards the eyes, the circlet of hairs, 

 the spines on the hind margin of the carapace and on the fourth 

 abdominal segment. Those, on the other hand, from S. R. 178, 

 S. R. 196, and S. R. 201 all possess some of the characters of 

 M. rugosa and some of those of M. bamffica. Several of those 

 in which the eye and circlet of hairs are of the rugosa type have 

 no spines on the middle part of the hind margin of the carapace, 

 and in some even the spines at the sides are wanting. Three 

 specimens, again, which have the rugosa type of eye and circlet, 

 have no spines on the dorsal surface. of the fourth abdominal 

 segment. 



