June, 1901] 



PSYCHE. 



211 



delicate duct, the vas deferens^ running 

 posteriorly from eacii to the ventral 

 wall of the penultimate segment. The 

 ovaries (of female specimens) are larger 

 and more elongate than the testes and 

 the oviducts (corresponding to the vasa 

 deferentia) are more easily seen. 



[Make a combined drawing showing 

 the alimentary canal, salivary glands, 

 tracheal trunks and reproductive organs 

 in position in the body]. 



The nervous system. Remove the 

 alimentary canal cutting the oesophagus 

 across near the front end of the proven- 

 triculus. The brain is composed of two 

 conspicuous white lobes united poste- 

 riorly lying above the oesophagus. The 

 sub-oesophageal ganglion lies beneath 

 and just below the oesophagus, and is 

 connected with the anterior end of the 

 brain lobes by the circum-oesophageal 

 commissures. Back of the sub-oeso- 

 phageal ganglion is a chain of four 

 closely connected ganglia. The next 

 ganglion is far removed from the fourth, 

 lying in the sixth segment and is con- 

 nected with the preceding and following 

 ganglia by long slender commissures. 

 Following the fifth ganglion are five 

 others similar to it, each lying over the 

 center of the sternal part of a segment. 

 Each ganglion gives off four very con- 

 spicuous nerve trunks : one on each side 

 arising from the middle of the ganglion 

 going to the muscles of the body wall. 

 and another arising from the anterior 

 end of the ganglion going to the viscera- 

 The last ganglion, lying in the antepe- 

 nultimate segment, in addition to the foiir 



lateral trunks gives off from the posteri- 

 or side two large divergent ones caudal 

 to the two following segments. [Make 

 a drawing of the nervous system.] 



TAe muscular system. Along each side 

 of the dorsal and the ventral median line 

 of the body is a wide band of longitudin- 

 al museies. The most conspicuous fibers 

 reach from the exterior to the posterior 

 border of each segment, but the others 

 reach from either end to the middle, 

 while others extend from the middle of 

 one segment to the middle of the preced- 

 ing or following segment, while still 

 others are attached to various points of 

 the body wall between the attachments 

 of the sets already mentioned. Finally 

 there is an innermost set of lateral trans- 

 verse muscles in the anterior half of 

 each segment. [Make a drawing show- 

 ing the musculation of two successive 

 segments.] 



[Remove a bit of muscle to a glass 

 slide and examine it with the compound 

 microscope. Note the transverse stria- 

 tion]. 



The circulatory system. [Cut a second 

 specimen open longitudinally along the 

 median line of the venter, reserving the 

 first specimen for some later work. Pin 

 the cut edges out. Note again the gen- 

 eral disposition of the body organs, so 

 far examined. Examine again the repro- 

 ductive organs ; the specimen may be of 

 the other sex from that previouslystudied. 

 Remove the alimentary canal.] The 

 dorsal vessel Qx heart is a slender, deli- 

 cate membranous tube composed of a 

 number of parts or chambers lying 



