382 Dr. C. Chilton on 



cularly on tlie branching holdfasts of Macrocysds. This 

 rendered necessary also an examination of the characters of 

 the other species of Limnoria that have been described during 

 recent years, and has led to one or two results which are 

 perhaps worthy of being placed on record. I have had for 

 examination numerous specimens of L. Ugnorum and of 

 L. segnis, and I have also been able to examine two speci- 

 mens from the Soutli Orkney Islands which appear to belojig 

 to L. antarctica, Pfeffer. These were found among the 

 " residues " o£ some Amphipodan collections made by the 

 'Scotia' Expedition in 1903, and were presumably taken 

 free, /. e. not boring into wood. 



In 1904, the Kev. T. R. R. Stebbing (1904, p. 714) 

 enumerated four species known at that time, with the 

 characters that appeared to distinguish them. Since t\\Q\\ 

 two other species have been described, making six species in 

 all. These species are : — 



1. Limnoria Ugnorum (Rathke), 1799. Lengtli 5 mm. 



Wood-borer, abundant in Europe and on the eastern 

 coast of North America, also recorded from the 

 Pacific and from San Diego, California. 



2. L. segnis, Chilton, 1883. Lengtii 5 mm. Species 



living on seaweed and not boring into wood, Lyttelton 

 and Akaroa Harbours, New Zealand. 



3. L. antarctica, PfefFer, 1887. Length 4*5 mm. Found 



in holes bored in seaweed. South Greorgia ; also taken 

 at tiie South Orkneys. 



4. L. ;/(#n, Stebbing, 1904. Length 3*5 mm. Found 



in rotten wood in lagoon, Minikoi, Indian Ocean. 



5. Z/.j/'apon/ca, Richardson, 1909. Length 5 mm. Taken 



from crevices in water-logged fragment of bamboo, 

 Japan. 



6. L. andrewsi, Caiman, 1910. Length about 2 mm. 



Boring in piles, Christmas Island, Indian Ocean. 



These six species form a very natural group, and are all 

 very much alike in size, general appearance, and in the 

 general form and structure of the different appendages. 

 They seem to differ mainly in the pro])ortions of some of the 

 mouth-parts and of the other appendages. The chief points 

 that have been used to differentiate them are the shape and 

 size of the epipod of the maxillipeds, the character of the 

 palp of the mandible, the relative size of the rami of the 

 uroj)ods and their proportion to the peduncle, and the 

 presence or absence of a comb-like spine on the propod of 

 the first gnathopod ; other distinctions have in certain cases 



