AND OTHER BRITISH PRAWNS. 103 



Adding 62 specimens from various localities on the East Coast 

 south of Norfolk the frequency is somewhat changed : — 



There seems to be a somewhat higher frequency for 9 dorsal 

 teeth than there is in Norfolk, but the number examined is not 

 sufficient for a definite conclusion. De Man's figures for 106 

 specimens from various localities are as follows : — 



Dorsal teeth : 9 8 7 



Individuals: 200/, 66 o/, 13 o/, 



In the tj^pical form of L. squilla from Scandinavia, De Man 

 found seven dorsal teeth in 31 per cent, of specimens and nine 

 teeth in 18 per cent. 



Such figures as these seem to indicate a definite local variation 

 in respect of this character, but in my opinion the material 

 examined is only sufficient to indicate a probability that such 

 variation occurs. 



Mandible palp. — L. squilla diflers from all other European 

 species of Leander in having the mandible palp two- jointed. 

 This difference was first pointed out by Dr. W. T. Caiman*, 

 but the palp was correctly figured by Ortmann in 1901 f, 

 though not alluded to in his definition of the genus Leander. 

 This character cannot be used in the determination of young 

 specimens 20 mm. or less, since, in L. longirostris at all 

 events, the mandible palp is still often two-jointed at that 

 size. 



Antennule. — The short flagellum is approximately equal in 

 length to the peduncle, but may be either shorter or longer 

 than it. This flagellum exceeds the length of the peduncle 

 more frequently in the male than in the female. The free 

 part generally exceeds the fused part in the proportion of 

 5 to 4. 



Second Leg. — The second leg reaches, when extended, beyond 

 the antennal scale by the whole chela or even by part of the 

 carpus as well. The dactylus is conspicuously shorter than in 

 the other species, being usually about one-third the length of the 

 whole chela. The carpus nearly alwaji's slightly exceeds the 

 length of the merus. 



De Man, as the result of the examination of large numbers of 



* See Kemp, " The Decapocla Natantia of the coasts of Ireland." Fisheries, Ireland, 

 Sci. Invest, i. 1908, p. 127 (1910). 



t " Die Klassen und Ordiuinsien der Arthropoden." Abth. Crustacea Malacostraca, 

 Taf. Ixxiv. fig. 2e (1901). 



