66 THE SCOTTISH NATURALIST 



1 8. P. gracilis (Fahrenholz). From Harvest-Mouse (Micromys 



minutus)} 



19. P. reclinata (Nitzsch). From Common Shrew {Sorex 



araneus)} 



20. P. serrata (Burmeister). From House-Mouse (Mus mus- 



culus). 



21. P. spiniger (Burmeister). From Water- Vole (Arvicola 



amphibius). 



22. P. spinulosa (Burmeister). From Brown Rat {Epimys 



norvegicus), Black Rat {Epimys rattus), and Alexandrine 

 Rat {Epimys rattus alexandrinus). 



Family ECHINOPHTHIRIID^E. 



Antennae four- or five-segmented. Legs with a thumb-like 

 process opposing the claw, the anterior pair small with slender claw, 

 the other pairs extremely large with blunt, heavy claws. Abdomen 

 without pleural, tergal, or sternal plates. Thorax and abdomen 

 thickly beset with spines or with spines and delicate scales. Occur- 

 ring only on marine mammals. 



Subfamily Echinophthiriin.e. 



Antennas four-segmented. Abdomen thickly beset with spines 

 but without scales. 



Genus Echitioplithirius Giebel. 

 Characters of the Subfamily. 



23. E. phoca (Lucas). From Common Seal {Phoca vitulind). 



Subfamily Antarctophthiriin^e. 



Antennae five-segmented. Thorax and abdomen beset with 

 many stout spines and with delicate scales. 



Genus Antarctophthirius Enderlein. 



Antennae five-segmented. Anterior legs and claws much smaller 

 than the others, which are extraordinarily large and stout. No 

 sternal plate. No pleural plates. Abdomen and thorax beset with 

 a great number of short, stout spines and with extremely delicate 

 scales. Spiracles small. 



24. A. trichechi (Boheman). From Walrus {Odobtenus ros- 



marus). 1 



1 Not yet recorded from Britain. 



