MUSEUM OF COMPARATIVE ZOOLOGY. 77 



EUMIERSIA, gen. nor. >, 



Resembles Pandalus in the external form of the carapax and abdomen, 

 and agrees with it essentially in the structure of the oral appendages, and 

 the two species known to me have the same number and arrangement of 

 branchiae and epipods as in the typical species of Pandalus ; but the genus 

 is more like Miersia in the structure of the thoracic legs, which, however, are 

 greatly more elongated than in the species of that genus here described, and 

 have only very small epipods at the bases of the fourth pair and none at all 

 upon the fifth. The mandibles, though essentially as in Pandalus, are stouter 

 and have larger molar processes^ while the ventral process^ are very thin, 

 more expanded, and with broader serrate tips, thus approaching somewhat to 

 the structure in Miersia. The mandibular palpi are much stouter than in the 

 typical species of Pandalus, and have broad terminal segments. 



Eumiersia ensifera, sp. nov. 



Plate Xm. Figs. 1-9. 



The carapax is as broad as high, with the cervical suture indicated by a 

 distinct sulcus from the dorsum to the upper part of the hepatic region either 

 side, where the sulcus terminates in a small but deep depression, and with a 

 very short and inconspicuous gastro-antennal sulcus ; the anterior margin is 

 armed with a small antennal and a distinct pterygostomian spine, though the 

 latter is wanting on one side in two of the specimens seen ; back of the cervical 

 suture the dorsum is very broad and evenly rounded, but there is usually a 

 very small dentiform tubercle in the middle line on the posterior part of the 

 cardiac region ; the rostrum in the smaller specimens is often not more than 

 half as long as the carapax proper, but in the larger specimens much longer and 

 in one specimen nearly as long as the carapax, nearly straight and horizontal, 

 or curved considerably upward as in the specimen figured, narrow, with a 

 strong ridge either side, tapering to a more or less acute tip, and with the 

 dorsal carina extending back upon the carapax nearly to the cervical suture 

 and armed with twenty-five to thirty'spines directed forward, raovably articu- 

 lated with the carapax, thickly crowded posteriorly but more and more remote 

 anteriorly, and of which six to eight are crowded upon the carapax in about 

 half the space between the orbit and the cervical suture ; beneath, the rostrum 

 is ciliated and in most of the specimens entirely unarmed, but in two or three 

 cases there are one or two teeth near the tip. 



The eyestalks are short and terminated by small hemispherical black eyes 

 very nearly as in Miersia Agassizii, The peduncle of the antennula is about 

 half as long as the antennal scale : the first segment is about as long as the two 

 otheis taken together, excavated above for the reception of the eye, which, how- 

 ever, does not reach by a considerable distance the extremity of the segment, 

 ■with a prominent lateral process terminating in an acute spine, and the body 



