190 Mr H^my Goodsir on a Nm G^nm, ^a^ 



strong spines ami the iiiterspHce : claw stroirg and bent : slightly fl»t- 

 tened on its superior edge. 

 Second and third thoracic segments very short, wanting about a third 

 of the length of the first thoracic : fourth segment equal in length to 

 either of the two former : fifth and sixth pcdiculated, last almost glo- 

 bose. Segments of all the posterior legs lengthened j last joint of the 

 last pair with a tooth on its inferior edge near the base : claws strong. 

 This species may be distinguished from Caprella linearis^ 

 with which it is most apt to be confounded, by its greater 

 comparative size, the structure of the antennae ; by the short- 

 ness of the post-occipital segment ; the situation of the swel- 

 ling on the first thoracic segment, which is at the posterior 

 edge, whereas in the linearis it is at the anterior ; the femo- 

 ral joint of the second pair of legs is not clavate in the line- 

 aris, and is also quite straight. 



Plate III. Fig. 8. 



Caprella linearis. — Superior antennae reaching to the middle of third 

 thoracic segment : head very deep : post-occipital segment extremely 

 short, almost of the same length as the head. Swelling at the anterior 

 extremity of the first thoracic segment. Femoral joint of the second 

 pair of legs almost as long as the first thoracic segment : last joint oval j 

 one tooth on its lower edge near the base. Lengthy half an inch. Hab. 

 Frith of Forth. 



Description. — The whole body almost colourless : very fragile. Head 

 very deep, being almost twice as deep as the post-occipital segment. 

 Superior antennae reaching almost to the middle of the third thoracic 

 segment. Last joint composed of about twelve articulations. Inferior 

 antennae hardly so long, and strongly fringed with spines on its lower 

 edge. The post-occipital segment is extremely short, hardly so long as 

 the head itself. First thoracic segment twice as long as the head and 

 post-occipital segment: the swelling is situated near the anterior extre- 

 mity at this part : it gives off a small branch from which the second 

 pair of legs arises. The femoral joint is not clavate, quite straight^ and 

 of no great length, not being so long as the first thoracic segment : last 

 joint oval, almost globular, and armed with one tooth on the inferior 

 edge near its base. Claws small. Second and third thoracic segments 

 of equal length ; second more slender. Branchial lamellae small and 

 situated near the middle of the segment. Fifth and sixth thoracic seg- 

 ments pediculated. The posterior thoracic legs almost moniliform ; 

 an almost obsolete tooth being placed on the inferior edge near the 

 base of distal segment of the last pair of feet. 

 This appears to be the Caprella linearis of authors ; there 



are some marks of difference, but they are trivial, and not 

 sufficient to authorize any new specific distinctions. 



