5286 



Crustacea. 



hair ; while the margins of the central plate are armed with long and 

 short denticulations. 



This species seems to approach in its characters to My sis vulgaris 

 and M. Griffithsise of Bell more nearly than to others; but it differs 

 from both in having the apex of the central caudal plate truncated, 

 and the rounded angles armed with two large and diverging spines, as 

 well as in having the other margins armed alternately with large and 

 small teeth. The rostrum is about the size of that of M. vulgaris, 

 while the antennal scale is not more than half as long as in that spe- 

 cies, as well as being wider and rounded anteriorly. Compared with 

 M. Griffithsiae, the rostrum is not more than half as long, while the 

 antennal scale is longer and wider, and both have the external spine. 

 From these considerations I am inclined to consider it as specifically 

 distinct from both. 



Mysis Lamorn^e. 



Specific characters. Rostrum obtusely triangular ; antennal scale 

 reaching beyond the peduncle of the internal antennae; the central 

 caudal plate deeply bifurcated, and about half as long as the second. 



Mv»js Lamoenje. — 1. Lateral view. 2. Dorsal view. 3. Magnified dorsal view of rostrum, &c. 4. Cau- 

 dal extremity. 0. Legs. 



Habitat. Under overhanging rocks along the margin of the tide- 

 way, near low water. Not uncommon. Mount's Bay. 



