SG On Hersllia (Clausidlum) vancouverensis. 



Antennules bent upwai'dsj numerous hairs on upper edge. 



Maudibles bearing a tooth with smooth edges aud having 

 a row of hairs (PI. 11. fig. 2). 



Considerable gap between maxilhpeds aud first thoracic 

 legs. 



Fifth thoracic leg broad, with a few fine hairs (fig. 3). 



Infects Callianassa pugettensis. 



Hah. Near Nanaimo, Vancouver Island. 



The other appendages of the females of the two species are 

 similar. 



The males of the two species are alike, except that the 

 antennules are bent as in their respective females and the 

 Vancouver Island form is slightly larger than the one from 

 Naples. 



Literature. 



1839. Hersilid apodiformis, Pliilippi. " Eiuige zoologisclie Notizeu." 



Archiv fur Naturgesch. Tafel iv. figs. 9-11, p. 128. 



1840. Hersilin apodiformis, Philippi. H. Milne-Edwards, Hist. Nat. 



des Crustaces, tome iii. pi. xxxvii. fig. 23, p. 417. 

 1866. Ilersilia apodiformis, V\i\\\])\)i. C. Heller, " Carcinolog. Beitr. zur 

 Fauna der adriat. Meeres." Verhandl. zool.-bot. Gesellsch. 

 Wien, P)d. xvi. p. 750. 



1874. C/ausidiian testndo, Kossmann. " Ueber Claiisidium .... &c." 



Verhandl. phys.-med. Ges. n, F. Bd. vii. Taf. vi. 



1875. Ilersilia apodiformis, Philippi. Glaus, " Neue Beitriige z. Kennt. 



par. Gop." Zeitschr. f. wiss. Zool. Bd. xxv. 1, Taf. xxii. 

 1888. Hersilia apodiformis, Philippi. Ganu, " Les Copepodes mai'ins 

 du Boul. (1 ) iii." Bull. Sc. de la Fr. et de la Belg. iii. ser. 1, 

 t. xix. p. 406. 



EXPLANATION OF PLATE II. 



Lettering, 



«?? = antennule ; rtn' = antenna; ^=lower lip; wi = mandible; mx= 

 maxillule ; m.i' = niaxilla ; j??.?;^— maxilliped ; ^ = tooth of mandible; 

 /eZ= telson ; f7i'-M'' = thoracic legs 1-5. 



Fig. 1. Hersilia vancouverensis, sp. n. Female, with diminutive male 



attached to the lower part of the abdomen. 

 Fig. 2. Mandible of Hersilia vancouverensis. 

 Fig. 2 a. Mandible of Hersilia apodiformis (Philippi). 

 Fig. 3. Fifth thoracic leg of Hersilia vancouvereyisis. 

 Fig. 3 a. Fifth thoracic leg of Hersilia apodiformis. 



