126 Mr IT. Goorlsir on the Genus Ciima. 



found to be very material. In its general appearance, this species resem- 

 bles the Cuma Edwardsii. The first thoracic segment, however, is longer 

 and not so rounded ; the rostrum is shorter and more pointed, and the eyes 

 are larger ; the flattened surface on the sides of this species is not so de- 

 cided. The second thoracic segment is more hid ; the third is larger, 

 ovoid, and rounded; the adjoined 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 clavatc. The superior antenna; are verj^ small, and 

 scarcely to be distinguished from the rostrum. The inferior antennso 

 are very similar to those of the Cuma Edu-ardsii. The foot-jaws are 

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

 ambulatory 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 composed of one -joint only, as in the last described 

 species, consists of four or five segments, which are all aimed with 

 short spinlferous and pointed spines ; the natatorj' portion of this le^ 

 is multiarticulate, the extreme joints being very small, so as to place 

 the long spiniferous sctse very close to one another.* 



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

 similar in their structure to those of the last described species. The ab- 

 domen and caudal fins also bearing a similar resemblance. 



This species is apparently the Cuma Audouinil of M. Edwards, but 

 ■whether it is or not I cannot be quite certain. 



Cuma trispinosa, mihi.+ 



C. — With the dorsal ridge of the caraface 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, 8 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 pre- 

 ceding. 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 rostrum is sharp-pointed, 

 and bent considerably upwards ; the eyes are small, and the dorsal 

 ridge immediately behind the eye is surmounted with three thick short 

 spines. The second thoracic segment is of considerable extent at its 

 dorsal part, but is quite obsolete at the middle ; it again, however, 

 makes its appearance at its inferior part, where it supports the second 

 pair of compound legs. The four following segments gradually de- 

 crease in size : — The superior antennaj are of considerable size, oblong 

 and spinous. The inferior antennae are much longer than the rostrum. 

 The ambulatory division of the first pair of legs is extremely short, and 



• Plate II. Fig 19. t Tlato HI. Fig. 1. % Plate IV. Fig. IG. 



