Annelida of St. Andrews. 149 



M. purpurea^ and CanneUa annulata are found in great beauty ; 

 Avhile the intricacies in the roots of tlie tangles afford favourite 

 sites for Nemertes gracilis and others already mentioned. The 

 diibris in the fishing-boats is especially productive of fine 

 examples oi Amphiporus pulcliev ?i\\di Micrura fasca^ j both, 

 besides the ordinary method of progression, swimming grace- 

 fully through the water like freshwater leeches, by throwing 

 themselves on edge and striking right and left alternately 

 with their flattened tails. The curious Nemertes carcinophila 

 is abundant on the o vigorous abdominal hairs of the females of 

 the shore-crab. 



Almost all the Nemerteans live well in confinement ; and 

 while the development of several is known, that of others 

 (such as Nemertes Neesit, N. gracilis, Linens marinus, L. 

 sanguineus, the Micrurce, and Garinella annidata) affords a 

 fine field for further research. The Nemerteans approach the 

 Annelids proper very closely. 



The Rhabdocoela are generally minute, but tolerably numer- 

 ous amongst the red ascidians hanging from cavern-roofs, or 

 algous and zoophytic growths on the under surface of stones, 

 in tidal pools and near low-water mark. 



The Planarians are fairly represented, the common forms 

 frequently occurring under stones between tide-marks, and 

 gliding over the surface of rock or glass like a living skin, 

 which requires a keen eye for detection. When much disturbed 

 they swim a short distance through the water, with a horizontal 

 stroke that has been compared by some to the motion of a 

 skate'; but the undulation in the former is much greater than 

 in the latter, which has a gliding or skimming character. 

 They also progress on the surface of the Avater. Even more 

 active and irritable than the Nemerteans, they move with ease 

 and swiftness — never avoiding any small obstacle, but spread- 

 ing their thin mobile bodies over it, and continuing their 

 course uninterruptedly. Occasionally when a projecting point 

 is attained, the anterior part of the body is elevated and Avaved 

 to and fro till a convenient branch of seaweed or zoophyte is 

 reached. Some are very prettily coloured ; and though the 

 large and gaudily striped Eurylepta vittata, so characteristic 

 of our southern shores, is not found, yet the pink and yellow 

 hues of Planaria ellipsis are scarcely less attractive. The 

 little Planaria uhxv, which abounds in the brackish waters of 

 many of the creeks on the western coasts, is absent. The 



* A fine specimen of the large Cerebratulus angulatus, O. F. IMiillev, 

 was sent me from the neighboirring Bay of Montrose by Dr. HoAAalen ; 

 but imfortunately no proboscis was present. The two forms closely ap- 

 proach each other. 



