226 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. INTRODUCTION. 



My study of the nervous system of certain annelids was begun in the 

 summer of 1895 at Wood's Hole, at the suggestion of Prof. C. O. Whit- 

 man, who proposed that I should if possible ascertain the nature of the 

 metamerism of Clymenella torquata, as expressed in its nervous system. 

 This species proved to be poorly adapted to the elucidation of this ques- 

 tion ; but the investigation of the nervous system has been continued 

 during my two years of study at Radcliffe College, under the direction 

 of Professor Mark of Harvard University. The work undertaken at 

 Wood's Hole was confined to Clymenella torquata, but the discovery of 

 a new worm, Clymene producta, and the use of special methods of pres- 

 ervation, furnished me the material that first suggested an investiga- 

 tion of the so called giant fibres and giant cells. Sections of this worm 

 killed in vom Rath's fluid gave me remarkably satisfactory preparations 

 of many parts of the nervous system, especially of the giant cells and the 

 sensory organs. 



The two polychaete annelids with which this paper deals are members 

 of the family Maldanidse. One, Axiothea * (= Clymenella) torquata, is 

 found in the sand flats of many regions of our New England coast. The 

 other belongs to a different genus. It is a new species, which I found in 

 one of the small harbors opening into Vineyard Sound. I have found it 

 in only this one locality, although I have examined the sand flats of many 

 parts of the shore. Its distribution would seem, therefore, much more 

 limited than that of Axiothea torquata. In a recent description (Lewis, 

 '97) of this new worm, I have proposed for it the name Clymene pro- 

 ducta, the specific name having been chosen on account of the great 

 length of the worm. It is sufficient here to state that this worm can be 

 readily distinguished from Axiothea torquata by the much greater num- 

 ber of segments which it possesses, and by a series of red bands upon the 

 anterior abdominal segments. 



The nervous systems of these two worms, both the central system and 

 the sense organs, present many interesting features, the description of 

 which must be omitted from the present paper ; such, for instance, as the 

 eyes of the new species, and in case of both worms the ciliated grooves of 

 the head. 



* As I have shown in a recent paper (Lewis, '97), there is not sufficient ground 

 for retaining the generic name Clymenella, proposed by Verrill, since the worm 

 described under that name clearly belongs to the genus Axiothea of Malmgren. 



