Description of Genera and Species. 73 



Crangopsis rhodesi sp. nov. PI. XI., figs. 11-14. 



Specific Characters. — Small slender form a little over 1»» mm. in length. Carapace 

 long and narrow, deeply emarginate behind and with a broad band bordering its side 

 wings and the posterior margin. Epiraera of tail segments obtusely pointed and directed 

 backwards. The epimera of the second tail segment do not overlap on to those of the 

 first. Peduncle of antennules long and slender. 



General Description. — This is an elegant shrimp-like form with elongated bod\', 

 laterally compressed, and fossilising sideways. The integuments are thin and smooth, 

 but usually much wrinkled in the fossil state. 



In the trunk, the loosely attached carapace is narrow and elongated, measuring 

 considerably more than one-third of the length of the body. There is only a very slight 

 peak in front corresponding to the rostrum, but there appears to be a slight crestal 

 keel, and a blunt projection in the place of the orbital spine and one also at the 

 antero-lateral angle. The wings are extended far back, the postero-lateral angles being 

 well rounded, and the carapace is usually deeply emarginated behind. The wings and 

 the posterior margin are bordered by a characteristic, somewhat broad, double border 

 which serves to distinguish fragments of the carapace of this species from some of the 

 others. Owing to the length of the trunk the segments composing it are set at a 

 somewhat more acute angle to the axis of the body thati in any other species of the 

 genus. 



The tail is of the usual fusiform shape, being deepest about the second segment and 

 tapering gently backwards. The segments increase in length in order backwards, and 

 the last segment is nearly double as long as ain' of the others. They are aU supplied 

 with deep epiraera with l)lunt pointed ends directed slightlj' backwards. Those of the 

 first segment are well overlapped by the wings of the carapace. Those of the second 

 segment are the deepest and longest, but they do not overlap on to the posterior margin 

 of the epimera of the first segment as in the case of several species of the genus. The 

 epimera of each segment only overlap on to those of the succeeding segment in rotation 

 backwards. They also diminisli in depth in succession from the second segment, and 

 are only slightly represented on the sixth segment. 



The telson is comparatively short, is grooved down the mid-line, and produced 

 into a terminal lobe bej'ond its constricted part, where the two small accessory plates 

 or swimmerets are articulated with it. It differs from that of C. socialis in liaving its 

 antero-lateral angles ornamented with a thickened band ending in a backwardly-directed 

 spine on each side at about one-third of the distance from the base to the tip (fig. 12). 



