GENERA CUMA, ALAUNA, AND BODOTRIA. 



329 



scale projects backwards ; the fourth segment is of the same shape as the third, 

 but not nearly so large ; the fifth ends in a sharp point, both superiorly and 

 inferiorly ; the sixth thoracic segment is clavate. The superior antennae are 

 very small, and scarcely to be distinguished from the rostrum. The inferior 

 antennae are very similar to those of the Cuma Edwardsii. The footjaws are 

 also similar in their structure to those of the last-described species ; the am- 

 bulatory division of the first leg is five-jointed ; the first joint is very much 

 bent, and is of considerable breadth ; the two last joints are quite oval, and 

 the last nonchelate. The internal thumb-like process, instead of being com- 

 posed of one joint only, as in the last described species, consists of four or five 

 segments, which are all armed with short spiniferous and pointed spines ; the 

 natatory portion of this leg is multiarticulate, the extreme joints being very 

 small, so as to place the long spiniferous setas very close to one another. 



The second pair of legs are very short. The last four pairs of legs are similar in 

 their structure to those of the last described species. The abdomen and caudal 

 fins also bearing a similar resemblance. 



This species is apparently the Cuma Audouinii of M. Edwards, but whether it is 

 or not I cannot be quite certain. 



Cuma trispinosa, mihi. 



<7._With the dorsal ridge of the carapace surmounted by three spines, with the 

 ambulatory division of the first pair of legs extremely short, and with the second 

 thoracic segment well developed. Long, eight lines. Hab. Frith of Forth. 



Description. This is a most characteristic species, and brings out several points 

 of material consequence in the character of the genus. This species has the 

 body quite smooth, and of the same colour as the preceding. It is the largest 

 of all the species, but is more slender. The thoracic segments are not so deep 

 as those of the preceding species, and the lateral compression is awanting. The 



