98 BRITISH PARASITIC COPEPODA. 



the large dorsal plates which the female possesses. 

 The frontal sinus is also not so pronounced. 



1. Cecrops latreillii Leach. 



(Plate XXI, figs. 3, 4; Plate XXVII, figs. 9, 10; 

 Plate XXVIII, figs. 1-7.) 



1816. Cecrops latreillii Leach. (74) p. 20, and five figures. 



1850. Cecrops latreillii Baird. (4) p. 293, pi. xxxiv, fig. 1. 



1857. Cecrops latreillii Hoeven. (61a) Mem. d'Entoniol. de la Soc. 

 Entom. des Pays-bas, vol. i, p. 67, pis. iii & iv. 



1892. Cecrops latreillii A. Scott. Trans. Nat. Hist. Soc. Glasgow, 

 vol. iii, pt. 3, p. 266. 



1900. Cecrops latreillii T. Scott. (112) p. 157. 



1907. Cecrops latreillii C. B. Wilson. (148) p. 468, pis. xxxviii & xxxix. 



1909. Cecrops latreillii E. V. Elwes. (45) p. 20. 



1910. Cecrops latreillii T. R. R Stebbing. (125) p. 558. 



Female. Carapace oval, stout, length and width 

 nearly equal, deeply emarginate in front, and with the 

 posterior margin deeply excavated. Second and third 

 thoracic segments apparently coalescent and forming 

 one segment which bears a dorsal plate with broadly- 

 rounded lateral lobes. The last thoracic segment with 

 a tolerably large dorsal plate, the front margin of 

 which is nearly straight, but posteriorly of a semi- 

 circular outline and reaching to near the middle of the 

 genital segment; a narrow and moderately deep cleft 

 or sinus dividing the plate in the median line at its 

 posterior margin. The dorsal plates of the genital 

 segment nearly twice as long as the carapace and 

 extending backward so as to conceal the abdomen and 

 caudal rami ; their inner margins contiguous and 

 apparently coalescent, forming a single plate which is 

 \vider than the carapace and terminates posteriorly in 

 two equal and broadly -rounded lobes; the genital 

 segment covered by these coalescent plates narrow and 

 flattened, and the abdomen and caudal rami small. 



Antennules two-jointed, end joint small. Antennas 

 armed with strong, hooked, terminal claws. Second 

 maxillipeds stout, terminal claws strong and hook- 

 like. All the four pairs of thoracic legs biramose and 



