I, Si' COPEPOPA. 



also at Plymouth amongst weeds at low water of spring-tides, 

 August 22nd, 1903. 



PORCELLIDIUM TENU1CAUDA, ClaUS. 



1860. Porcellidium tenuicauda, Clans, Beitr. z. Kennt. d. Entomost,, 



i. Heft, p. 6, pi. ii. tisrs. 10-18. 

 1880. Porcellidium tninicavtla, Brady, vol. ii. p. 166, pis. Ixix. 



fig-s. 10-13 ; Ixx. tig. '>. 

 1889. Porcellidium tenuicanJa, Clans, Copepodenstudien, i. Heft, 



Peltidien, p. 33. 



Porcellii/itnn deiitatum, Claus, is the young of this species. 



This interesting and rare form was not observed in the 

 gatherings examined by us, but Dr. Brady records having 

 dredged a specimen off St. Agnes, Scilly Islands, in a depth 

 of ten fathoms. 



POROELLIDITM LECANOIDES, Cluus. (Pis. XIV. fig. 12; XV. 



fig. 5; XIX. fig. 3; XX. fig. 7.) 



1889. Porcellidium lecanoides, Claus, Copepodenstudien, i. Heft, 

 Peltidien, p. 33, pi. ix. tigs. 1-33. 



A single specimen of this Porcellidium was taken at the 

 mouth of the River Yealm, South Devon, 18<S9. Though this 

 specimen approximates somewhat closely to P . jimbriatum in 

 the form of the caudal lamellse, the armature of these append- 

 ages agrees better with that of the caudal lamella? of the 

 species to which the specimen is ascribed and which is repre- 

 sented by the drawing (PI. XIX. fig. 3 ; see also PI. XX. 

 fig. 7). 



In this specimen the antennules are short, moderately 

 stout, and composed of six joints ; the first three joints are 

 large but the last three are short ; the third joint is about 

 equal to the first but is only about two-thirds the length of 

 the second, the fourth is scarcely more than half the length 

 of the preceding joint, while the two end joints are subequal 

 and very small "(PI. XV. fig. 5). 



The fifth pair of thoracic feet are in the form of moderately 

 elongated and narrowly subtriangular plates (PL XIV. 

 fig. 12), but which do not reach to the extremity of the 

 caudal segments. 



Caudal segments moderately narrow and subcylindrical, 

 extending distinctly beyond the apices of the abdominal 

 segments, and each furnished with about five short but 

 moderately stout setae on the somewhat obliquely truncated 

 extremity ; one of the setae springs from the outer and another 

 from the inner angle, while the other three are situated on 



