PHILORTHRAGORISCUS SERRATUS. 141 



only reaches over two-thirds of the former, just till a 

 couical spine that arises from the middle of the inner side 

 of the basal joint , upon a broad hump-like base ; at the 

 opposite side, the joint bears a much smaller papilliform 

 process , surrounded by a spoon-shaped cavity , formed by 

 a prolongation of the upper margin of the foot-jaw. Pro- 

 bably this papilla is homologous with the palplike appendage 

 of the Dinematura-iooi-isLW . The terminal joint is connected 

 with the basal one by a broad articulation ; at its concave 

 side, next to its base, it bears a small spiniform seta. 

 This limb more resembles that of Dysgamus , than the 

 more composite one oï Dinematura. The first pair of swim- 

 ming feet (fig. 6) is more slender than in Dinemattcra and 

 shows more resemblance with that of Echthrogaleus ; it is 

 furnished with two two-jointed branches , the inner of which 

 is short and does not reach beyond the extremity of the 

 proximal joint of the outer branch. The terminal joint of 

 both branches bears at the inner side three long plumose 

 setae; moreover that of the outer branch is provided with 

 four marginal spines, of which the two middle ones bear 

 a secundary point near the apex. The distal joint of the 

 inner branch is without spines, but it is externally fringed 

 with hairs. A spine is visible at the exterior and the in- 

 terior angle of the basal joint of the foot. 



In the structure of the second pair of swimming feet 

 (fig. 7) the difference from those of Dinematura and Ech- 

 throgaleus is already more pronounced ; the first of them 

 has both branches , the other one the outer branch three- 

 jointed, whereas in our species both of them consist only 

 of two joints. 



Kröyer published a detailed description of these feet, 

 so not much needs to be added. In contrast with the first 

 pair of feet both branches here are nearly of the same 

 length, and in both the proximal joint bears at the inner 

 side a plumose seta; at its lateral side it is provided 

 in the outer branch with a row of short, curved mar- 

 ginal spines, which is produced at the ventral side over 



JS^otes from the Leyden Museum, "Vol. XIX. 



