272 ANNALS OF SCOTTISH NATURAL HISTORY 



another specimen turned up in my garden, which is within the muni- 

 cipal boundaries of Perth. The species does not occur within many 

 miles of Perth, so that it must have been introduced in some way 

 probably with plants from one of its mountain habitats. At the 

 same time I have no recollection of having recently brought into the 

 garden any plants on which there would likely be the eggs or larvae. 

 It is possible, therefore, that it may have been brought some years 

 ago, and established itself amongst the Saxifrages (its food plant), of 

 which I have a number growing. It will be interesting to see if it 

 appears another season. The specimens were rather smaller and 

 darker in colour than Highland individuals. F. BUCHANAN WHITE, 

 Perth. 



Argissa (Syrrhoe) hamatipes (Norman) in the Firth of 

 Forth. This apparently rare amphipod has been obtained in the 

 Forth during the past summer. The only previous British records for 

 it known to me is that given by Rev. A. M. Norman in his Shetland 

 Report for 1868, and that published a short time ago by Mr. David 

 Robertson in the proceedings of the Natural History Society of 

 Glasgow. Argissa hamatipes ( = Argissa typica, Boeck) resembles 

 Ampelisca in form, and might be mistaken for a member of that 

 genus, but an examination of the eyes of Argissa reveals a very 

 curious structure that at once distinguishes it from Ampelisca. The 

 eye consists of four pairs of lenses arranged at about equal distances 

 round the edge of a somewhat circular patch of diffused pigment. 

 In the male also, the median dorsal part of the third last segment of 

 the pleon is produced backward over the next segment in the form 

 of a free tooth-like process, and is one of the more obvious characters 

 by which the species may be identified. G. O. Sars describes and 

 figures Argissa in his "Crustacea of Norway," vol. i. page 141 

 (1891). THOMAS SCOTT, Leith. 



Modiodieola insignis (Aurivillius) in the Firth of Forth. Some 

 time ago, when examining specimens of the "Horse Mussel" 

 Mytilus modiolus, from the Firth of Forth, several specimens of a 

 prettily coloured copepod were observed which appeared to be 

 Modiodieola insignis, Aurivillius. It seems to be a commensal 

 rather than a parasite of the mussel, and is found harbouring about 

 the branchial lamellae. It is frequently of a brilliant pink colour 

 when alive, even the ovisacs when present being of the same colour. 

 Modiodieola is closely allied to the genus Lichomolgus from which it 

 differs in the form of the footjaws and in one or two other characters. 

 Several specimens of this copepod are sometimes found in a single 

 mussel, and fully half the number of mussels examined contained 

 specimens. It may be of interest to state in contrast to this 

 example of commensalism or semiparasitism, that though many 

 specimens of the common (edible) mussel Mytilus edulis from 

 various localities have been examined, no copepod has hitherto been 



