NOTES ON THE FAUNA OF FALMOTJTH. 261 



taken by the hitherto rare brittle star Ophiocoma nigra, which 

 abounds in a deep hole near the West Narrows buoy. Here, 

 after strong westerly winds, the dead leaves of Zostera marina 

 have a tendency to accumulate, and one's dredge will frequently 

 come up half filled with decaying portions of this weed, inter- 

 mingled with splendid specimens of Ophiocoma nigra and 0. 

 fragilis. 



Crustacea. Portunus depurator occurs in considerable 

 abundance on the Truro oyster beds. I have secured upwards 

 of six specimens of this pugnacious crab in one haul of my 

 dredge on more than one occasion. P, puber was found " in 

 berry " on the 12th of March. This species has long been 

 recognized amongst collectors as the most quarrelsome of its 

 class; an unexpected "nip" from one of these crustaceans 

 while shore-hunting is not likely to be soon forgotten. During 

 the spring tides of March, when the sea recedes beyond its 

 ordinary limit, examples of this crab were fairly numerous 

 under stones. The weather was exceptionally cold during this 

 time, and this fact may in some measure account for the 

 following circumstance. These crabs were found to have lost 

 their usual pugnacity, and under no circumstances could be 

 induced to assume their fighting posture. Later in the year, 

 when the weather was warmer, fchey were as vicious as evex. 

 The integument in all the specimens on all occasions was hard ; 

 no soft crabs of that species could be found in the spring. 

 Galathea squamifera occurs in abundance along all the shores of 

 Palmouth harbour. Indeed it is by no means unusual to find a 

 dozen or more specimens of that species under one stone during 

 low water. A single specimen of Gralathea squamifera was 

 found under a stone near St. Just Creek on the 13th of March, 

 with the right side of the cephalothorax abnormally swollen. On 

 dissecting away a portion of the integument a very fine female 

 specimen of Pleurocrypta galatheoe, Hesse, was discovered. 

 Fortunately the diminutive parasitic male was also present, so I 

 was able to make a careful study of both. About twelve months 

 later another example of Gralathea bearing a similar parasite 

 was found inside a hollow beam of timber in the Docks. These 

 are the only two specimens of Pleurocrypta I have ever secured. 



