SOME AQUATIC WORMS, ETC. 189 



The eggs vary considerably in external ornamenta- 

 tion, showing three paterns. In one, the ends and 

 one side bear low, stout, hollow processes, whose 

 apices are truncate, and four- or five-parted when 

 viewed from above. In another, the appendages 

 are long, hollow, conical spines, whose distal ends are 

 trifid or quadrifid,. the branches in profile appearing 

 very fine and delicate, but when viewed from above 

 are seen to taper to the ends, where each terminates 

 in a widely spreading furcation. In the third form, 

 one side and both ends are covered by an irregular 

 network of raised lines, the meshes being four- or five- 

 angled, while the opposite side is rugose with fine, 

 minutely sinuous lines. 



Fig. 139.— Chaet6notus spinifer. Fig. 140.— Chjetdiiotus acanthdphorus. 



6. Ch^t6notus acanth6phorus (Fig. 140). 

 The superior surface of the head and neck and the 

 lateral body-margins are clothed with recurved prickles 

 or short spines, while the dorsal region proper bears 

 four rows of long thorns, each row arched towards the 

 head, and each formed of five unequally furcate spines, 

 with an additional one on both sides near the pos- 

 terior extremity. The spines rise from an enlarged 



