Report on the Crustacea Schizopoda of Ireland. 239 
Distribution.—Falmouth ; Plymouth; Seaham; N. Wales; E. and W. Scot- 
land (A. M. N.*). 
Norway; Sweden; Denmark; Naples; Black Sea (A. M. N.*). 
Genus Macropsis, G. O. Sars. (See Note added in Press, p. 250.) 
Genus Macromysis, A. White. 
Macromysis flexuosa (Miiller). 
Not in the Survey Collection. 
Marine Laboratory.—Aran ; Blacksod Bay ; Ballynakill; Inisbofin ; 1899. 
Museum, Dublin.—No. 85, 1893, Bantry Bay, per A. R. C. Newburgh. 
No. 122, 1892, Bantry Bay. 
No. 122, 1892, Dunbeacon Harbour, Bantry Bay. 
No. 122, 1892, S.W. of Ireland. 
Unregistered. Dunbeacon Harbour; Broadhaven, 1873; Merrion, Co. Dublin, 
joer Ci, MW, IDivxomn, 
Previous Irish Records.—* All our coasts’? (A. M. N.*). 
Distribution.—British coasts. 
Atlantic coasts of the European continent; Baltic; Black Sea(?), (A. M. N.*). 
Of all British Mysidee with which we are acquainted, the genus Macromysis 
appears to present the greatest difficulty in the determination of the species, on 
account of the unsatisfactory nature of the characters by which J. flexuosa and M. 
neglecta have been separated by Sars and Norman. Were it not for the high 
authority of these observers, we might be inclined, with little ceremony, to relegate 
one species to the synonomy of the other, a proceeding hardly justified by our 
experience of the family. We must, however, admit that we have never seen a 
really typical specimen of I, neglecta as redefined by Norman. The distinctive 
characters of the two may be summarised (from Norman) as follows :— 
M. neglecta. M. flexuosa. 
Antennal scale.—Ca. 5 times as long as 7 to 8 times as long as broad; more 
broad; not twice the length of than twice the length of peduncle 
peduncle of antennule ; apex of antennule ; apex scarcely ex- 
extending twice the length of tending beyond spine. 
spine of external margin. . 
Tarsus.—5-articulate, last 4-articulate. 6-articulate, last 5-articulate. 
Telson.—Cleft + of total length, very Cleft + of total length, moderately 
narrow and constricted at base; open; 21 to 27 lateral spines. 
18 to 20 lateral spines. 
Length.—20 mm. 25mm. 
2L2 
