202 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



Superiorly, the notopodium carries tAVO transverse rows ol 

 more slender organs of a similar nature, the setm : the proxi- 

 mal set are much shorter than the distal, but even the latter 

 do not attain a length of more than j^g of an inch (Fig. 52, 



The proximal set are somewhat knife-like in shape if viewed 

 in profile, consisting of a comparativeh' short, straight "han- 

 dle," by which they are imbedded in their sacs, and of a thick, 

 rounded, curved blade, tapering to a fine point at its extrem- 

 ity. Close-set transverse ridges, finely serrated at their edges, 

 and inclined obliquely to the surface of the blade, traverse 

 its convex anterior circumference, leaving the back free. The 

 distal set^ (Fig. 52, G) have a very similar structure, but they 

 are much elongated and very slender. The handle is longer ; 

 and the blade, little curved and simply set on an angle with 



Fig. 52. — Polynde sQuaonata. 



A, elvtron viewed from above. B, a tooth. C D, nenropodial setae. F, F, parts of 



the blade of the earae, more highly magnified. G, free extremity of a notopodial 



peta. 



the handle, is produced at the end into a long and delicate 

 filament. The base of the blade {E) is beset with incomplete 



