312 Mr. J. W. Pryde on Annelida FohjcJiccta 



the ' Challenger* forms. The second segment is broad and 

 bears the first pair of feet, which are much stouter than 

 tliose of O. britannica or O. conchylega. They are directed 

 forwards and in some specimens reach almost to the frontal 

 tentacles. Their tips have disc-like processes, which are 

 poorly developed in many of the young forms. The first 

 feet in the young forms are broad iu comparison with their 

 length, and the cirri are relatively longer than in the adult 

 specimens. The posterior subulate papilla which springs 

 from behind the disc-shaped flap at the tip of the foot iu the 

 adult examples is very rudimentary, and in some cases 

 absent in the young forms. The feet in both are supported 

 by three or four stout yellow spines, while the bristles, only 

 one or two appearing above the surface iu the young speci- 

 mens, are strongly hooked at the tips, beneath which are 

 well-developed secondary processes. 



The tenth foot is very much smaller than the first, and 

 toward the tail the feet become smaller still. The dorsal 

 cirrus, however, is very large, fusiform in shape, and tapers 

 toward the ti]), while the ventral cirrus only appears as a 

 ventral pad. The same condition holds good for the young 

 forms. Three or four spines again support the setigerous 

 region of the feet, from which dorsally there project one or 

 two long l)ristles with winged and tapering tips, besides a 

 group of brush-shaped ones. The papilla at the posterior 

 border of the tip is lanceolate and in the young form is just 

 a mere excrescence. The terminal process has now become 

 smaller, the disc-shape having become more conical. The 

 same applies to the young examples. 



When the thirtieth foot is reached the dorsal cirrus has 

 become very slender, and from the inner edge of its base 

 arises a branchia which is more than twice its length. 

 Prof. MTntosh says that this organ is slightly fusiform in 

 outline, but iu the present examples it presents a somewhat 

 constricted appearance. The setigerous region is almost 

 round, and in none is there a papilla present at the tip. 

 Posterior to this foot the branehise diminish in size ; but, as 

 the Monograph remarks, "the arrangement of the bristles 

 and hooks remain the same/'' 



The tubes are translucent horny objects resembling 

 quills, which, according to recent investigations, the animals 

 drag after them. Their composition has not yet been 

 definitely agreed upon, but some eminent chemists think 

 that the substance is allied to mucin. At both ends of the 

 tubes there are apertures which are closed by valves and 

 which do not allow the contained fluid to escape uutil they 



