60 DUBLIN NATURAL HISTORY SOCIETY. 



type, and frequents pools which are less frequently visited by the tides. 

 In colour and other characteristics I find such a close accordance, I must 

 look on the characters drawn from the beak as not of specific importance, 

 the only other difference being in the comparative weakness of the di- 

 dactyle hands. The following are the varieties in the number of teeth 

 of the rostrum met with: — Apex bidcntate, above 7-10, below 2-4; 

 apex simple, above 7-9, below 2-3 ; the commonest form being 7 or 8 

 above, apex bidentated, and 3 below. 



Belfast (W. T.), Dublin, Galway; doubtless confounded with P, 

 serratus in lists. 



P. Leachii. — I have seen no authentic Dublin specimens of this spe- 

 cies; all those shown me either preceding species, or P. varians. I have 

 collected specimens in Galway, and Professor Melville showed me nu- 

 merous specimens collected there by him. The specimen thus named in 

 J. V. Thompson's collection is not this species, but the variety (?) of P. 

 ttquiUa, described above. 

 Dublin (?), Galway. 



Mysis chameleon. — Much commoner than I formerly stated; very 

 abundant in sand-pools ; in ova in March, April, and May. The ova 

 are easily hatched, and the young are similar to the parent when ex- 

 truded. 



Before concluding, it may be interesting to compare the relative dis- 

 tribution of the genera and species in the east and west, when we arrive 

 at the following results, excluding from our comparison those strange 

 forms, Bodotria, Alauna, &c. 



Brachyura. 



Common to both districts, 23 



Unrecorded in east, made up as follows : — Achaeus, 

 Pisa, Maia, Xantho (3?), Portunus (2), Ebalia (?), 

 Thia. Those genera peculiarly typical italicized, . 10 



Unrecorded in west, 



Brachyuri, — 33 

 Anomoura. 



Common to both, 11 



Unrecorded in east, viz., Pagurus (1), Miinida (?), . 2 

 Unrecorded in west, viz., Pagurus (1), Galathea (1), 2 



Anomoura, — 15 

 Macroura. 



Common to both, 11 



Unrecorded in east, viz., Crangon (2), Alphaus, 



Ntka, Athanas, Palsemon (1), Hippolyte (1), . . 7 

 Unrecorded in west, viz., Hippolyte (1 ), Crangon (2), 



Palsemon, 4 



Macroura, — 22 



Stomapoda, common to both, 2 



Omitted in above list, 8 



— 10 



Total Crustacea podophthalmia, . - 80 



