120 journal of Entoiiiolog) anil Zoolof;) 



group of animals. In it he shows in some forms a marked dorsal 

 ganglion and a ventral ganglion with the typical nerves. Burger 

 showed that all ganglion cells are unipolar, without membranes. 

 Montgomery, 1897, discusses the ininute anatomy of the ner\e 

 cells. Coe, 1895 and 1910, considers the general anatomy of the 

 ner\ous system, but ner\e details are for the most part not shown. 



In a young Carhiclla chiyuldtci Cole which I have studied by 

 means of reconstructions, I find no unusual features. The nervous 

 system is typical of the group. The brain, however, is not \ery 

 clearly made up of two lobes on each side. I'his may be because 

 the specimen used was a young one. This may also be the reason 

 why the brain is not sharply marked off from the lateral nerve cords. 



Figure 1 shows the brain and part of the lateral cords from the 

 \entral side. From the two hahes of the brain come the ner\'es to 

 forvvaril parts. Fhe small dorsal commissure is shown with its 

 usual median extension. Prom the larger ventral commissure come 

 the two nerves to the proboscis, lateral to these are the ner\'es to 

 the intestine, while from the ridge of the lateral cords the lateral 

 ner\es are shown. 



I'igure 2 in the larger tlrawing at the right shows the nersous 

 system as \iewed from the side with the dorsal side to the left. 

 The central core of the ganglion and cord is to indicate the posi- 

 tion of the Hber area. The small drawings at the left show \ arlous 

 levels of the nervous system as seen in cross section. The \entral 

 side is up. The drawing at the top is through the brain before the 

 commissures are reached, the next lower is through the thickest 

 part of the brain anil the lower two drawings are through one ol 

 the lateral cords. 



Hiiiyer, O. 1891 



Beitarge ziir kenntnis ilcs Nervens\st<'ms lier Wirbellosen. Neiie 

 Unter. iiber ilas .Nrivt-ns\>tem der Nciiif rtitifii. Inst. a. il. Zool. Sta. 

 Neah. 10. 



Burner, O. 1890 



Heitragf /.iir Kcmitnis des Ncr\cii>\ stems dcr Ncmi'itincn. Zcit. 

 Wiss. Zool. H.l. L. 



1895 



Die Nenicrtinen. 



I'aiina u. Flora il. (Jolles v. Neapel. 



