12 



SALPIIX^i:. 



be brought under the focus at once, their peculiar arrangement is 

 readily understood. The chain (Fig. 5) consists of two rows of 



Fig. 354. 



(Fi- 5.) 



individuals jilaced slightly ol)li(iuely to the axis of the chain, in 

 addition to the natural obliquity of the individuals on the right 

 and left sides. The ventral side is always turnetl outside, and the 

 individuals are placed back to l)ack at an angle measured by the 

 obliquity of the endostylcs, wliich is quite considerable. Besides 

 this oldique arrangement of the ventral and dorsal sides, the an- 

 terior and posterior extremities are not on the same level; the 

 anterior extremity is tilted up so that all the anterior openings are 

 brought to the upper side of the chain when it is floating, and the 

 l>osterior openings close to the edge on the lower side ; the ante- 

 rior o]»ening is |)laced at a short distance from tlie edge of the 

 chain, thus bringing, by tliis arrangement, the anterior and pos- 

 terior openings on different sides of the chain. Adjoining individ- 

 uals are connected liy the two large dorsal S])urs of the anterior 

 extremity of tlie respiratory cavity. The next ])air of individuals 

 lap over the first ]»air of the chain very considerably, so far that 

 the nucleus of the first ])air is Just l)elow the nervous ganglion of 

 the second pair. The right individual of the anterior pair is con- 

 nected with the individual innnediately behind it l)y the small spur 

 behind the nucleus, while it (the right-hand individual of the sec- 

 ond pair) coiHiects witli its adjoining i'ellow in the same way as 



