68 Mr. C. Spence Bate on a neiv Genus of Macrura. 



broad across the cardiac and branchial regions ; but this can- 

 not be clearly defined, as the laterally projecting tubercles 

 are somewhat damaged either by the action of the gastric 

 juices during the incarceration of the specimen in the dol- 

 phin's stomach or from manipulation afterwards in its dried 

 condition. 



Tlie anterior portion or frontal region is narrow and de- 

 pressed, the central line being produced anteriorly into a 

 small rostrum, on each side of which is a slight concavity 

 or hollow space for the greater freedom of the movements of 

 the ophthalmopoda and antenna. The antero-lateral angle is 

 anteriorly projected downwards as a strong point or process 

 that is slightly curved, and on the upper or dorsal surface 

 is produced into a strong process or horn which is projected 

 upwards and slightly curved backwards at an elevation higher 

 than the median line of the gastric region, which lies as a 

 plane between the two lateral prominences and separated 

 from them by a deep and narrow fissure. The cardiac region is 

 surmounted by two large tubercles that are separated from each 

 other longitudinally in the median line. Both lateral promi- 

 nences are circular at base, tipped with small tubercles, and 

 mammiform in appearance ; posterior to these on each side is a 

 row of three tubercles continuous to the posterior margin of 

 the carapace. On the outer or lateral side the branchial 

 region is produced into large protuberances, the surfaces of 

 which are not clearly distinguishable, from external injury; the 

 lateral walls are curved inwards on the lower surface, leaving 

 only a narrow space between them, in which lies the posterior 

 portion of the pleon and the rhipidura or tail-fan. 



The pleon is narrow, smooth, and laterally compressed ; 

 the telson tapers posteriorly and terminates in two processes, 

 one at each postero-lateral angle, and on its inner margin 

 bears a series of six sharp teeth which gradually increase in 

 length, and the lobe is tipped with a smooth spine 5 

 millim. long. The telson is also armed on each side with 

 three small spines — one near the middle, a second halfway 

 between the first and the posterior extremity, and the third 

 rather nearer than halfway between the preceding and the 

 posterior extremity. 



The carapace is about 9 millim. long. 



The pleon is about 6 millim. 



The telson is about 2 millim. 



The ophthalmopoda (PI. IX. fig. 1, a) are long and broad, 

 the ophthalmus being large, pear-shaped, and projected upon 

 a slender biarticulate peduncle. 



The first pair of antennae {h) are short, the first joint is 



