x36 BULT.ETIN OK THE 



Holl, Massachusetts, and in 1879 he established a new genus Nectonema 

 with the type species N. agile,^ regarding it as a jS[ematode of uncertain 

 systematic position. 



Dr. J. W. Fewkes ('83, p. 201) was the first to figure this form; he 

 also gave a short account of its external anatomy. But unfortunately 

 both text and figures are somewhat inexact. 



Last summer there appeared a paper by Dr. 0. Biirger ('91) on the 

 anatomy and histology of Nectonema, which placed beyond question its 

 affinity to the Nematodes, and for the first time furnished evidence as 

 to the details of intei-nal structure. His work, was based on material 

 collected at Newport in 1885, but, as he himself says, it consisted of 

 only a few specimens, and these were not in good histological condition. 

 The gaps in his description, as well as the eri'ors, which were largely 

 due to insufficient and poorly preserved material, influenced me to carry 

 out my work, which was already well advanced before the receipt of his 

 paper. For the sake of comparison it will be more advantageous to 

 consider under the appropriate topic the various points of structure 

 which he describes, rather than to give a connected resume of his paper 

 at this place. 



The material at command for the following study consisted of four- 

 teen specimens, collected and preserved with great care at Newport last 

 summer, besides those received from other persons. From Dr. E. A. 

 Andrews I received five, which he had collected at' Wood's Holl in 

 1890, and from Dr. W. M. Wood worth one^ which was obtained at the 

 same place in 1888. Professor Verrill, at the solicitation of Dr. Agassiz, 

 very kindly sent me his entire collection, consisting of thirty-five speci- 

 mens taken in Vineyard Sound between 1875 and 1883. For all these 

 kindnesses, and especially to Professor Verrill for his courtesy in supply- 

 ing me with personal information on numerous questions addressed to 

 him, I desire to return my sincere thanks. To Dr. Agassiz I am deeply 

 indebted for the hospitality of the Newport Marine Laboi-atory last 

 summer, and for permission to use his notes and drawings, as well as 

 for many other favors. To Professor E, L. Mark I owe much for valu- 

 able suggestions, and for his continued personal interest in the progress 

 of the work. 



Methods. 



Nectonema is certainly an animal which it is difficult to preserve 

 well. This is largely due to its resistent cnticula, which hinders the 



1 iV. ugdis, Verrill, '79, p. 187. 



