BELONGING TO THE GENEEA BKADYA AND ECTINOSOMA. 429 



The lahiuni consists of a bifid and strongly-hooked j)rocess, a lateral view of which is 

 shoAvn in the figure (PI. 36. fig. 27). 



Both pairs of foot-jaws are somewhat similar to tliose of Ectiiiosoma Sarsi (PL 37. 

 figs. 32 and 55). 



The first four pairs of swimming-feet are also somewhat like those of that species ; 

 but in the first pair the inner branches are proportionately shorter, while lioth branches 

 in the fourth pair are of nearly equal length, and the second basal joint of the same pair 

 is furnished Avitii an elongate slender spine on the exterior angle (PL 38. figs. 9 and 23). 



The produced inner portion of the fifth pair is cylindrical in form, the length of which 

 is equal to about one and one-third times the breadth; the secondary branches are 

 nearly quadrangular in outline — the length only slightly exceeding the breadth; tlie 

 armature of the fifth pair is somewhat similar to that of Ectinosoma Sarsl (PL 38. 

 fig. 34). 



Caudal stylets short, but rather longer than broad and a1)out equal in length to the 

 last abdominal segment. The posterior margins of the abdominal segments are all 

 more or less fringed with cilia. 



Habitat. Firth of Porth, off Musselburgh. 



Memarks. This species comes near Ectinosoma Sarsi, Boeck, but difl'ers in the following 

 particulars : the proportionate lengths of the joints of the antennules are greater, the 

 mandible is furnished with more small teeth on its biting-edge than that of E. Sarsi, 

 the anterior foot-jaws are stouter, the armature of the swimming-feet is somewhat 

 weaker, and' the fifth feet are much shorter, being nearly as long as broad. 



Ectinosoma gracile, sp. n. (PL 36. figs. 18 and 37; PL 37. figs. 13, 28, 45 ; PL 38. 

 figs. 3, 27, 30.) 



Description. Length -7 mm. (^^ of an inch). Body seen from the side very slender, 

 nearly cylindrical. Rostrum prominent. Antennules (PL 36. fig. 37) elongate, slender, 

 composed of seven joints ; the penultimate joint is nearly equal to the combined lengths 

 of the two preceding joints, as shown by the annexed formula : — 



No. of the joints : 1.2.3.4.5. 6 .7 



Proportional lengths : S 8 5 8 4 11 4 



Antennae elongate, moderately stout ; the secondary branches small and 3-jointed, not 

 reaching to the end of the second joint of the primary branches ; the first two joints are 

 short, the other elongate, being nearly twice the entire length of the first two (PL 37. 

 fig. 13). 



Anterior foot-jaws elongate, moderately stout ; the end-joint about twice as long as 

 broad, and armed at tlie extremity with two long slender claws and two elongate slender 

 setee (PL 37. fig. 28). 



Posterior foot-jaws slender, considerably shorter than the anterior foot-jaws ; end-joint 

 about half the length of the preceding one (PL 37. tig. 45). 



Inner branches of the first four pairs of swimming-feet moderately slender and 



57* 



