On a neic Si^ecies of Sessile- eyed Crustacean. 73 



X. — Description of a new Species of Sessile-eyed Crusta- 

 cean, and other Notices. By the Rev. Thomas R. R. 

 Stebbing, M.A. 



[Plates IV. & v.] 



Microdeuteropus bidentatus, n. sp. PI. IV. figs. 1,1 a, lb. 



This new species of Microdeuteropus was dredged at Sal- 

 combe in August of the present year (1875). It exhibits 

 well the characters of the genus as given by Messrs. Bate 

 and Westwood, if we except the expi*ession '"'' complexly sub- 

 ehelate," which they apply to the first gnathopods. This 

 complexity, however, does not belong to all the species 

 they describe, nor to the females of any of them. The genus 

 Autonoe of Bruzelius Avas separated from Microdeuteropus of 

 Costa to receive species which do not possess the complexity 

 in either sex, and which have the rami of the last pair of 

 pleopoda unequal. But the separation seems scarcely desirable, 

 since there appears to be no correlation between the two cha- 

 racters used for the generic distinction. Thus the present 

 species and M. longipes, at least as described in the 'Cata- 

 logue of Amphipodous Crustacea,' have the rami of the last 

 pleopoda equal, but the hands not complexly chelate. On 

 the other hand, M. grandimanus, also described in the Cata- 

 logue just mentioned, has the rami of the pleopoda unequal, 

 but the posterior angle of the carjras of the first gnathopods 

 produced into a tooth in the male — a circumstance which 

 links it closely to the M. gryUotalpa of Bate and Westwood, 

 M. anomalus of Rathke. 



In general appearance the new species has a near re- 

 semblance to M. Websteri. The superior antennae have a 

 secondary appendage of three slender articulations, and a 

 flagellum of fifteen. In the lower antennse the articulations 

 of the flagellum are comparatively stout, but only four in 

 number. The eyes are small and black. The whole animal 

 is slender, and, like others of the genus, when dead has a 

 metallic lustre. The telson has a double apex, carrying two 

 short spines and two setae. The last pair of legs exceeds in 

 length the preceding pair by the whole of the long thin pro- 

 podos and finger ; the antepenultimate pair is the shortest ; 

 the third and fourth pairs are equal in size, having the finger 

 two thirds the length of the propodos. The thighs of all the 

 seven pairs of legs are long ; those of the second gnathopods 

 are distinguished by a sort of curved spur projecting at the 

 anterior distal angle ; in other respects this pair of gnathopods 



