lOG Mr. W. II. Tattersall on tiew 



I think these three larval Tremato'les are new to our 

 fauna ; no othir stages in their life-history have yd been 

 fouiul. 



EXPr>ANATION OF THE PLATES. 

 Plate VII. 



Treiiiatoile from Cardhnti eihde. 



A. Sporocysts eiiclosiiif? cercarise. 



B. C'ercaria pressed out of cyst. 



C. Tailed cercaria. 



Plate VIII. 



A ct B. Trematode from Purpura lajnl/us. 



A. Cercaria. 



B. Ivedia enclosing cercaria?. 



C & D. Trematode from Patella vulyata. 



C. Cercaria. 



D. lledia enclosing cercariaj. 



X. — Preliminartj Diagnoses of Six new Mysidse from the 

 IVest Coast of IreJand. By W. M. Tattersall, B.Sc, 

 Departmeut of Agriculture and Technical Instruction, 

 Fisheries Branch, Dublin. 



The six new forms, of which preliminary descriptions are 

 now offered, were captured off the southern part of the west 

 coast of Ireland in depths ranging from 4G5 to 800 fathoms, 

 bv the S.S. ' Helga/ the fishery cruiser of the Department 

 of Agriculture for Ireland. These depths have been but 

 rarely reached by the bottom-fishing apparatus of the ' Helga/ 

 and tlM3 fact that thus early in their exploration six new 

 species of Mysidee have been brought to light suggests the 

 existence of a fauna rich in undescribed forms. 



All six species belong to the subfamily Lejjtomy since * of 

 the Mysidie. Two are types of new and interesting genera, 

 while the other four belong to two recently defined deep- 

 water genera characterized by the imperfectly developed eyes 

 possibly modified for tactile functions. 



Genus Metamblyops, nov. 



Characters generally as in Amblyops, G. O. Sars, except : — 

 Carapace produced in front into a well-developed, rather 

 long and acute rostrum. 



* I cannot agree with Nonnan's recent proposal to raise his sub- 

 families to family rank {cf. Norman and Scott, * Crustacea of Devon and 

 Cornwall,' London, 1906). 



