L.M.B.C. TUKBELLARIA. 55 



larian fauna of the several districts. With the briUiant 

 exception of Claparede's paper, the observations are fre- 

 quently too fragmentary to allow us to accurately determine 

 the species that are mentioned. A very valuable addition, 

 therefore, to our knowledge is the description of 34 marine 

 forms obtained by Professor von Graff during a two 

 months stay at the ''Ark" Millport, N.B. This list 

 incorporated in his "Monograph" of the group (1882) 

 furnishes a basis of comparison with other part of our 

 coasts. For the last ten years, however, little work has 

 been done on British Marine Turbellaria. 



We may next consider how and where marine Turbel- 

 laria are to be found. Dividing the group for our present 

 purposes into the flat leaf-like Polyclads 1 cm. or so long, 

 and the small, usually cylindrical Bhabdocoels rarely more 

 than 2 mm. in length, the following methods have proved 

 successful. The Polyclads are to be found by extremely 

 careful search on the under surface of weed-covered stones 

 between tide-marks. Almost all forms are coloured in 

 such a way as to remain unobserved unless the keenest 

 vigilance be exercised. Infra-littoral species occur among 

 shells, polyzoa and hydroids dredged at various depths up 

 to 20 fms. The Khabdocoeles being minute cannot be 

 directly observed on the shore. It is necessary to collect 

 sea-weeds, stones covered with diatoms, ascidians, &c., 

 the sand at the base of corallines, and to place these sep- 

 arately in vessels containing sea-water. The Turbellaria 

 will presentl}^ emerge and can be found by searching the 

 sides of the vessel with a hand-lens. Dredge-material 

 treated in like fashion will yield numerous forms constitu- 

 ting a fauna fairly distinct from the littoral one. For 

 Polyclads I have found the coast near Port St. Mary to 

 be the best. For Ehabdocoeles, the Calf Sound and tide- 

 pools round Port Erin have proved most productive. 



