88 BRITISH PARASITIC COPEPODA. 



Habitat. Parasitic usually on the porbeagle shark, 

 Lamna cornubica. Berwick Bay, 1834 (Dr. Johnston). 

 Polperro, Cornwall (A. M. Norman). Moray Firth 

 off Dunrobin, and at Aberdeen Fish-Market (T. Scott). 

 Near Shetland (G. B. Wilson). On a thrasher shark, 

 Alopias vulpes, at Buddon, Firth of Tay, in 1887 

 (Prof. d'Arcy W. Thompson). Recorded also from the 

 Greenland shark, Scymnus glacialis. 



Distribution. European waters. Atlantic coast of 

 North America. 



Genus 13. ECHTHROGALEUS Steenstrup $ Liitken, 



1861. 



Female. Carapace, antennae, and mouth-appen- 

 dages nearly as in Phyllortkragoriscus, but the dorsal 

 plates of the last thoracic segment larger. The genital 

 segment, which is also large, extending backwards so 

 as to overlap and conceal wholly or partially the 

 abdominal segment and caudal rami ; the postero- 

 lateral lobes of the genital segments rounded at the 

 end and separated by a tolerably deep sinus which 

 may be narrow as in E. coleoptratus or moderately 

 wide as in E. dentirnl(itnx. 



Thoracic limbs as in Pht/llorthragoriscns except that 

 the inner ramus of the second and third pairs are 

 composed of two instead of three articulations. 



" Male. Carapace like that of the female but pro- 

 portionately larger, frontal plates more prominent. 

 Lateral lobes of second thoracic segment corresponding 

 to the first pair of dorsal plates in the female ; no 

 lobes on the third segment ; a rudimentary pair on 

 the fourth segment which are closely appressed to the 

 anterior margin of the genital segment. The latter 

 smaller than in the female, with one pair of legs at or 

 just in front of the posterior corners. Abdomen 

 small and two-jointed ; anal lamina large and armed 

 with plumose setae. Appendages as in the female." 

 (C. B. Wilson.) 



