SEA-FISHERIES LABORATORY. 119 



Pseudocaligus brevipedes (Bassett Smith). 



Found attached to the inner side of the operculum of 

 the three bearded rockling, Onus tricirratus. This genus 

 is distinguished from Caligus, its nearest ally, by the 

 structure of the fourth pair of feet, which have no 

 exopodite. 

 Lepeophtheirus pectoralis (Miiller). 



Our experience of this species is that it occurs more 

 frequently on the flounder than on any other member of 

 the Pleuronectida?. The pectoral and pelvic fins often 

 have their under surfaces covered with this parasite ; on 

 one occasion thirty-two adult females were counted 

 adhering to a pectoral fin. Males and immature females 

 appear to be more common on the general surface of the 

 fish. 

 Lepeophtheirus nordmanni M. Edwards). 



This is one of the larger species of Lepeophtheirus, and 

 sometimes measures half an inch in length. It is found 

 on the short sun-fish Orthagoriseus mola. 

 Lepeophtheirus hippoglossi (Kroyer). 



Found generally distributed on the surface of halibut, 

 occasionally in considerable numbers. On the " white *' 

 side of one specimen we have counted 100 individuals, but 

 that was on a fish in the Aberdeen fish market. 

 Lepeophtheirus stromi (Baird). 



Frequently found on the salmon captured in the 

 estuaries. Its black metallic lustre makes it a con- 

 spicuous object on the bright scales of the fish. 



Lepeophtheirus obscurus, Baird. 



From the gills and inner surface of the operculum, 

 and under the pectoral fins of the brill. It is probable 

 that this species may only be a form of L. thompsoni, 

 Baird, which is found on the gills of the turbot. 



