NOTES 



165 



the shore, there are two or three narrow ditch-like pools, which, 

 owing to their muddy beds, are probably seldom, if ever, quite dry. 

 It would appear that only exceptionally high tides in spring 

 and autumn reach them, and that for the greater part of the year 

 they receive only rain water. Although doubtless always to some 

 extent brackish, the salinity of these pools can never be otherwise 

 than low. 



In one of these pools, on 8th March last (1913), I noticed 

 numbers of prawns, which proved upon the examination of a few 

 secured for identification to be the interesting Palamonetes varians 

 (Leach). Revisiting the locality on 14th June, I found them still in 

 abundance, and this time many of the females were carrying clusters 

 of eggs. Of 40 captured by drawing a small net through the muddy 

 water, 19 were egg-bearing females, the rest being males and 

 immature females. Palcemonetes varians is an addition to the list of 

 Forth Crustacea, as recently catalogued by Dr Thomas Scott {Proc. 

 Roy. Phys. Soc, vol. xvi.) ; but it has been recorded from the north- 

 east coast of Scotland by the late George Sim {Trans. Nat. Hist. 

 Soc. Aberdeen, 1878, p. 86), and from the Clyde by Dr J. R. 

 Henderson {Proc. N. H. Soc. Glasgow, 1886), and Dr Scott 

 {Fauna, etc., of Clyde Area, 1901). 



Interest attaches to P. varians in several ways. While in the 

 northern portion of its range it appears only to occur close to the 

 sea in water that is, to some extent at least, brackish, in the 

 Mediterranean region it is found almost exclusively in fresh water, 

 being present even in lakes far inland; and the curious fact has 

 been observed that its development is much abbreviated in the 

 south, as compared with what takes place in this country and other 

 parts of Northern Europe. The great variation in the number 

 of teeth on the rostrum has also attracted the attention of 

 naturalists. 



According to Bell {Brit. Stalk-eyed Crustacea, 185 1) the species 

 is characterised by having the rostrum entire at the apex, and armed 

 above with 4 to 6 teeth, beneath with 2. Weldon, however, in 1890, 

 showed {fourn. Mar. Zool. Assn., i. N.S., p. 459) that at Plymouth, 

 where he examined 915 individuals of both sexes, the apex is more 

 often bifid than simple ; while the number of dorsal teeth ranged 

 from 1 (in two cases) to 7 (in one case), and of the ventrals from 

 o to 3 above and 2 beneath. Four above and 2 beneath were his 

 most frequent numbers. Quite recently, Stanley Kemp {Fisheries, 

 Ireland, Sci. Invest., 1908, i. [1910]), in a useful tabular statement of 

 the characters of the British species of Palasmonidoe, describes the 

 rostrum in P. varians as armed dorsally with 3 to 5 teeth, which do 



