318 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



deepening of the water, the tidal belt is considerably- 

 curtailed, and the shore fauna necessarily scanty. 

 Towards the mouth of the Firth the following species 

 are commonly met with, under stones at low- water : 

 Galathea squaviifera, Porcellana platycheles, Portunus 

 puber, Cancer paguriis, and Eiipagurus Bemhardus, 

 In the rock pools we find Palaevion sqidlla, Mysis 

 flexuosus, and Hij^polyte varians, and on the sandy 

 shores Crancjon vulgaris. As compared with the 

 Crustacean fauna of other parts of Britain, we miss 

 in the tidal zone the species of Xantho^, Gebia, 

 Alpheus, and CalUanassa, so characteristic of the 

 Southern shores; while Arctopsis tetraodon, Athanas 

 nitescens, and Palaetnon serratus, also a|3pear to be 

 absent. In the laminarian zone occur Hyas araneus, 

 Homarus gajii'tnarus, species of Hijyj^ohjte, Palaemon, 

 and various Mysidae. Passing next to the coralline 

 zone, which, in the Firth of Clyde, inchides the greater 

 part of the hard or stony ground, we find Crustacea 

 to be much more numerous both in number of species 

 and individuals. The extensive nullipore banks at 

 Skelmorlie, the Tan (Cumbrae), and Lamlash Bay, 

 afford shelter to many interesting forms. There, 

 especially, we meet with the various species of Por- 

 tuniis, Inachiis, and Stenorhynchus ; also Galathea 

 dispersa, G. intermedia, Porcellana longicornis, Pan- 

 dalus hrevirostris, Eupagurus Pi^ideauxii, Ehalia 

 tiiherosa, Euryno7ne aspera, and Hyas coarctatus. The 

 natives of Southern waters apparently conspicuous 

 by their absence, are, Crangon fasciatns, C. tri- 

 spinosiis,^ Polyblus Hensloicii, Portunus longipes, 

 Dromia vulgaris, Diogenes varians, Scyllarus arctuSj 

 and several species of Hippolyte, Palaenion, and 

 Mysidae. We also look in vain for the northern 



* Xantlio rivulosa is not uncommon in some parts of the 

 West of Scotland, and will yet, in all probability, be found on 

 the Arran shores. X. florida also occurs, though more rarely. 



t Crangon (risp'ino.'ms occurs along the East coast of Scot- 

 land as far as the Shetland Isles. It may yet be found in the 

 Firth of Clyde. 



