504 ARICIA LATEEILLII. 



and below the second or shorter papilla just mentioned. No strong spine-like forms can 

 be observed. The dorsal division of the thirty-first foot is like the preceding, but the 

 cirrus-like papilla to its exterior is larger, whilst its neighbour, also above noticed, has 

 now assumed a conical outline, is much larger, and has a broad base, whilst a small tuft 

 of long, slender, and finely spiked bristles projects from a furrow between a slight elevation 

 and its base. The papillae are present along the edge of the foot beneath, but all trace of 

 the curved spine-like forms and short slender bristles has vanished. 



The papillae behind the feet pass down to form a continuous row from side to side 

 for seven segments in front of the thirty-first, besides several imperfect rows before these, 

 and for five segments behind the thirty-first. 



The type of foot just described is modified only in a slight degree in its progress 

 backward to the tail. Thus at the fortieth foot the cirrus next the dorsal division is 

 longer, and the ventral setigerous process is bifid, whilst a ventral cirrus appears at its 

 lower border. The dorsal bristles have forked bristles with probe-points and spinous 

 inner edges amongst the others. The length of the ventral bristles has rather increased 

 and the spikes on the tips are directed distally. 



At the ninetieth foot the branchia has increased in size, whilst the dorsal cirrus is 

 narrower and smaller. 



In the feet some distance in front of the tail the branchia has notably increased in 

 size, and the dorsal cirrus is still knife-shaped, the intermediate cirrus being filiform, as 

 also is the tip of the long horn of the setigerous region and the ventral cirrus. The long 

 and strong dorsal bristles are only faintly serrated with spikes distally, and the forked 

 bristles continue. The tips of the ventral bristles are similar. 



No noteworthy change occurs till the diminution of the parts at the tip of the tail. 



In an example of this species procured in sand at low water, 15th June, 1904, there 

 were respectively thirty-one and thirty-three of the anterior segments with the deep- 

 brownish bristles. The eighth on the right, from injury, was out of line, and the seventeenth 

 was double, also apparently the result of an injury. The rows of ventral papillae began on 

 the twentieth and continued to the thirty-fifth, at which the specimen abruptly terminated. 



Reproduction. — In a female procured on 15th June the body ventrally and laterally 

 was of a dull yellow or buff colour from the masses of dull yellowish eggs, which occurred 

 in each segment. The eggs formed masses at the bases of the feet and were visible through 

 the dorsal wall. Such a condition seems to be common at this time. In section the ova 

 occupied not only the coelomic space on each side of the alimentary canal, but passed on 

 each side of the middle line between the dorsal longitudinal layer and the circular coat of 

 the region. 



Habits.— This species is a borer in sand, a life for which its mobile, pointed snout 

 and the conformation of its elongated body adapt it. It is not easy, however, to secure 

 perfect examples, especially if attempts are made to remove them from the hard sand. 

 When lying free in the water they sometimes keep up an undulatory movement of the 

 body as if for respiratory purposes. 



1 • Mitth. Zool. Stat. Nap./ xiii, p. 484. 



