122 MESSES. NOEMAN AND STEBBING ON THE 



followiug. Uropods with outer branch long and narrow, not arching 

 over the telson ; telsou narrow and Linceolate. Tlie whole animal 

 greatly drawn out and vermiform. Flagella of antenna; of both pairs 



many-jointed. Maxillipeds five-jointed Hzjssum\ n. g. 



Section B. Labium gradually tapering and acuminate, terminating in two 

 points. Mandibles without teeth, forming an acutely-pointed lancet- 

 like organ, and the saw-like process characteristic of the genera of 

 Section A is here represented by the expanding lobes of the base of the 

 lancet, which form a channel through which, when the incision has 

 been made, the liquid may be sucked. First maxillre take the form of 

 a greatly produced, very narrow, spear-like organ, which towards the 

 point is channelled on one side and finely serrated at the margins, thus 

 constituting an admirably adapted instrument for deeply probing tlie 

 wound where the lancet-like and more cutting mandible has first made 

 the incision. Maxillipeds are of great length, and consist of three or 

 four joints, of which the first is more than twice the length of the rest 

 combined. 



5. Segments of pleon distinct in the female. Lower antennae with a 



rudimentary flagellum. Upper pair having the Hagellum in the [Westw. 



male greatly developed into a long brush-like organ Paranthura, Bate & 



6. Segments of pleon distinct in the female. Antennae of both pairs in 



both sexes with many-jointed flagella (that of the upper pair not 



greatly developed in the male ?) Calatfivra', n. g. 



Genus 1. Anthura. 



1. Anthura gracilis (Montagu). (Plate XXV. figs, iii., iv.) 



1808. Oniscus gracilis, Montagu, Trans. Linn. Soc. ix. p. 103, pi. v. fig. 6. 



1813. Anthura ffracilis, Leach, Edinb. Encyclop. vii. p. 40-t ; Trans. Linn. Soc. xi. (1815) 

 p. 366; Desmarestj Consid. Crustac. p. 291, pi. slvi. fig. 13; Guerin-Meneville, Icon. Reg. 

 Anim. pi. xxx. fig. 6 ; White, Pop. Hist. Brit. Crust, p. 225, pi. xii. fig. 4 ; Gosse, Marine 

 Zoology, i. p. 248 ; Bate and Westwood, Brit. Sessile-eyed Crust, ii. p. 160. 



Segments of perseon with well-marked dorso-lateral keels ; telson abruptly truncate 

 and crenulated at the extremity. 



Head square, slightly produced at the centre and sides of the front margin. 



Perseon : first segment the longest, second to fifth subequal, sixth rather shorter, 

 seventh shortest of all, all bearing keels on each side on the back, and having a central 

 longitudinal keel on the ventral surface. 



Pleon in female having the five first segments indistinguishable and coalesced into a 

 single segment, which is equal in length to the last segment of the peraeon. In the 



' uoffds, u javelin, aud oipc'c, a tail. 

 ■ KaAo&os, a cup, and ovfia, a tail. 



