12 



SALPIl)^:. 



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

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



individuals placed idlghtly oljli(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 turned outside, and the 

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

 obliquity of the endostyles, whicli is quite considerable. Besides 

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

 terior and posterior extremities arc 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 

 posterior openings close to the edge on the lower side ; the ante- 

 rior opening is ])laced at a short distance from the edge of the 

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

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

 uals are connected by the two large dorsal sj^urs of the anterior 

 extremity of the respiratory cavity. The next pair of individuals 

 lap over the first pair of the chain very considerably, so far that 

 the nucleus of the first pair is just lielow the nervous ganglion of 

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

 nected with the individual immediately behind it by the small spur 

 behind the nucleus, while it (the right-liand indiviihial of the sec- 

 ond pair) connects with its adjoining fellow in the same way as 



