BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. Io! 
4. PLATYHELMINTHES, NEMATHELMINTHES, ETC. 
The various classes of “‘flat worms’’ are represented in our check list as fcilows: 
Turbellaria, 40(+1°); Trematoda, 52(+4?); Cestoda, 71(+3?); Nemertinea, 25 (1°). 
Of the ‘‘round worms’”’ there are 14 Acanthocephala and 21(+5?) Nematodes. The 
anomalous group of Chetognatha is represented by a single determined species of Sagitia, 
though there may be one or more undetermined members of the genus in local waters. 
The Dinophilea, which are included in the present section only for the sake of conven- 
ience, appear to be represented by at least three species, none of which, however, has 
been observed during the Survey dredgings. 
Except for a comparatively small number of nemerteans (6 species), no representa- 
tives of these groups of ‘‘worms’’ appear in the dredging records. Certain nemerteans 
are abundant locally in the shallow waters near shore, where they live under stones or 
burrow in the mud or sand; while Turbellaria of a considerable number of species are 
likewise common in shallow weedy waters. From the fragmentary condition of all the 
nemerteans which were dredged by us it is evident that the apparatus employed was ill- 
adapted to unearthing deeply burrowing worms such as these. It is likely, therefore, 
that our scanty records give a very imperfect idea of the distribution of these species 
throughout the area dredged. 
It was accordingly inevitable that the greater part of our data respecting these 
groups of organisms should be derived from previously published statements. The 
records for the Turbellaria and Nemertinea are based chiefly upon the works of Verrill 
and of Coe, supplemented, in the case of the latter group, by our own dredging records 
and by a set of manuscript notes kindly furnished by Prof. Coe.¢ The records for the 
endoparasitic worms (trematodes, cestodes, nematodes, and Acanthocephala) are based 
for the most part upon the works of Prof. Edwin Linton, who for many years has 
studied our local fish parasites on behalf of the Bureau of Fisheries. To these published 
sources of information we must add, however, some valuable unpublished notes, kindly 
put at our disposal by Dr. Linton. 
Acknowledgments for the revision of those portions of the checklist which include 
these groups are due Prof. Linton and Prof. Coe. To Dr. Coe we are likewise indebted 
for the identification of the nemerteans taken during the Survey dredging. We have 
thought it expedient to follow Dr. Linton in retaining provisionally in their earlier 
sense certain of the genera (e. g., Distomum), which have been greatly subdivided by 
some recent writers. In his own published works, Dr. Linton has taken occasion fully 
to acknowledge the invaluable assistance of Mr. Vinal N. Edwards, who collected a large 
part of the material described by him. 
Of the 41 Turbellaria comprised in our catalogue, 9 were listed by Verrill in the 
report of 1873, though only 2 of these were recorded specifically for points within the 
limits of our region. The records for most of the other species have been derived 
from Prof. Verrill’s later writings and from the recent report of von Graff. 
The number of Turbellaria which have been listed from Plymouth, England, is 
about fifty per cent greater than that contained in our catalogue, and so far as is apparent 
only two of the species are common to the two regions. Herdman’s list for the Irish 
Sea contains 27 members of this group. 
@ The additional records for T'urbellaria contained in the important paper of von Graff (1911) have also been incorporated 
during the revision of the present report. 
