BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. IOI 



4. PLATYHELMINTHES, NEMATHELMINTHES. ETC 



The various classes of "flat worms" are represented in our check list as fellows: 

 Turbellaria, 4o(+i?); Trematoda, 52(4-4?); Cestoda, 7i(+3?); Nemertinea, 25 (1 ?). 

 Of the "round worms" there are 14 Acanthocephala and 21 ( + 5?) Nematodes. The 

 anomalous group of Chaetognatha is represented by a single determined species of Sagitta, 

 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. a 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 sources of information we must add, however, some valuable unpublished notes, kindly 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. 



o The additional records for Turbellaria contained in the important paper of von Graff (191 1) have also been incorporated 

 during the revision of the present report. 



