of the Virginian Coast. 253 



The stout setae of the 5th segment are bluntly rounded 

 externally, either straight, or slightly curved at tip (f. 121). 

 Three or four short flat capillary setse curve around the 

 anterior margin of the first stout setae, and lie directly 

 across them. 



Ventral setae ; from the 7th segment stout, bidentate ; 

 lower tooth much longer than upper (f. 122), and covered 

 by membrane. They barely project from the surface ; are 

 curved within the body. 



Color. Anterior part flesh-color passing into white 

 behind. 



A single specimen was found living in a tortuous gallery, 

 excavated in a perfectly sound upper valve of Anomia 

 glabra Yerr. The gallery was lined by a membrane, which 

 formed a tube projecting about 4°'°' beyond the surface of 

 the shell. The channels in the tentacles were densely 

 covered with cilia. The long tentacles were almost con- 

 stantly protracted and moved about. The cilia of the 

 branchiae were very long and numerous. 



Length, 19°^; diameter, in front, 1°^™; behind, 0.5°^^ 

 This species can readily be distinguished from any pre- 

 viously described from our coast by the purple markings 

 on the tentacles. Though living in a gallery in a hard 

 shell, it lacks the dorsal hooks of P. hamata and P. hoplura 

 Clpd. 



Fam. AKICIID^. 



ARICIA {Sav.) Aud. & Ed. 



Aricia rubra n. sp, 



PL. rx, FIGS. 123-126, 



Branchiae beginning on the 6th setigerous segment. 



Head elongate, conical, pointed, as long as the first three 

 segments, having neither eyes, nor antennae. 



Branchiae: on the anterior segments nearly cylindrical 

 Trans, ix.] 33 



