186 BULLETIN OF THE 
Holl, Massachusetts, and in 1879 he established a new genus Nectonema 
with the type species N. agile! regarding it as a Nematode 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. O. Bürger (’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 internal structure. His work was based on material 
collected at Newport in 1885, but, as he himself says, it consisted of 
only a few specimens, änd these were not in good histological condition. 
The gaps in his description, as well as the errors, 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. Woodworth 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 Laboratory 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 continned 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 cuticula, which hinders the 
1 N. agilis, Verrill, ’79, p. 187. 
