I ( fl7 Pomona College .loin mil of Entomology mi,/ Zoology, I "/. IX, So. .>', September 



A Reconstruction of the Nervous System 

 of a Nemertian Worm 



W I I.I.IAM A. Ill I. TON 



Small specimens ol Carinella cingulula Cole were fixed in Mer- 

 curic chloride and cut in scries. A general hematoxylin stain was 

 very satisfactory for general anatomy. For a study <>l the liner 

 structure other preparations will be necessary. 



No attempt will be made to give a complete review oi the litera- 

 ture relating to this group. Almost every Systematic paper has 



something, because oi the importance ol the nervous system in classi- 

 fication and because in many cases the nervous system may be seen 

 through the body-wall without dissection. 



One ol the first extensive accounts ol these annuals which also 

 included quite a consideration ol the nervous system was Mcintosh 

 in 1874. Several oi the genus Nemestes were studied and the gen- 

 eral form oi the nervous system shown. Amphipheris is shown in a 

 similar manner with a single lobe ol the brain ami with the two 

 brain commissures. retrastemma is shown in a similar manner. 

 I Iubrccht m 1 S S 7 has an extensive paper in which the details ol 

 several nervous systems are shown as they show m reconstructions 

 Irom sections. Eupolia girardi is especially well shown with its 

 small dorsal and large ventral commissure and with three brain 

 lobes. It is in this paper that I Iubrccht makes Ins interesting com- 

 parison between the ncinertians and eordatcs. In his paper ol I S St ) 

 he has shown the structure and position ol different parts ol the 

 nervous system ol ncinertians, especially ol C crcbratulus ol which 

 he fjives a very good figure. In this he shows a reconstruction ol 

 the brain with its duel nerves, ventral and dorsal commissures, 

 general position ol the cells, (he two lobes ol the brain on each 

 side and the chic! nerves. Nc also treats ol nemertian nervous 

 systems ol many other forms, but not in so much detail. 



Burger in 1890, '91, has extensive papers on the nervous 

 system ol the group, lie discusses not only the general form, but 

 also the minute structure ol the nervous system ol a number ol dif- 

 ferent types. In 1895 Burger has another important paper on this 



