ANARTHROPODA, 133 
the organs of locomotion. They are distinguished from the 
higher forms by the fact that the locomotive bristles are com- 
paratively few in number, hence the modern name of the order 
(Gr. oligos, few; and chazte, a bristle). In the common earth- 
worm (Lumbricus terrestris) the body is cylindrical, attenuated 
at both ends, and furnished with eight rows of locomotive 
bristles. The mouth is destitute of teeth, and opens into a 
gullet which leads toa muscular crop, succeeded by a second 
muscular dilatation or gizzard. The intestine is continued 
straight to the anus, and is constricted in its course by numer- 
ous transverse partitions springing from the walls of the body- 
cavity. The pseudo-hamal system is well developed; and 
there exists in even greater numbers than in the leeches the 
series of segmental organs, or lateral pouches, which open 
externally by pores. The Vaidzd@ are chiefly noticeable on 
account of the power which many of them possess of producing 
fresh individuals by a process of budding before they attain 
sexual maturity. One of the commonest of them is a little 
worm which occurs abundantly in many of our pools and 
streams (Zudbifex rivulorum), and which exhibits a fine red 
colour, owing to the pseudo-hemal system being visible 
through the transparent integument. 
ORDER III. TusicoLa.—The Annelides included in this group 
derive their name from the fact ’ 
that they have the power of pro- 
tecting themselves by means of 
tubes (Lat. ¢uda, a tube; and 
colo, | inhabit). In some cases 
(fig. 60) the tube is composed 
of carbonate of lime, and is a 
genuine secretion from the body. 
In other cases, the tube is com- 
posed of grains of sand or 
pieces of broken shell, cemented 
together by a glutinous secre- 
tion from the surface of the Fig, 60.—Tubicola. a Serpula contor- 
body. In all the Tubicola the  ¢ufplicata, showing the branchize and 
respiratory organs are in the operculum ; 6 Spirorbis communis. 
form of branched filamentous external gills, in which the fluid 
of the pseudo-hemal system is subjected to the action of the 
