292 ANNELIDA POLYCHiETA ANDREWS. 



though rudimeutaiy ou a few terminal somites. Anus dorsal, sur- 

 rouuded by an oval series of papilhie 5 posteriorly a pair of very small 

 ones, next a much larger one ou each side, and then live subequal and 

 intermediate ones ou each side — fourteen in all. Seta^ of dorsal rami 

 loug, slender; those of first four somites more delicate and hair-like; 

 setie of ventral rami similar, but shorter, till twelfth segment is reached, 

 where hooked sette with lamella at tip appear, and gradually supplant 

 all but one or two of the capillary setse. Length, 25 millimetres ; diame- 

 ter, 1 millimetre. Color light; intestine dark; blood vessels conspicu- 

 ous, translucent posteriorly. Number of somites, one hundred. 



This interesting form was found in 50 per cent, of all the Ilyanassa 

 shells inhabited by the small hermit crab Uupagurus longicarpus Stimps. 

 and grown over by colonies of Eydractinia. It inhabits an imperfect 

 calcareous tube built in the terminal spires of the shell, and a tunnel 

 perforated through the columella to opeu externally just within the 

 aperture of the shell. From this aperture the anterior part of the body 

 is often extended. But one individual usually occurs in each shell; 

 sometimes a second smaller one was found in the spire, whether an 

 adult male or a young individual was not determined. 



The eggs and larvte in various stages are found within the Annelid's 

 burrow in August, as described in a recent number of the American 

 Naturalist. 



Family ARICI1D.E. 

 ARICIA (Sav.) And. aud Edw. 



Aricia oruata Verrill. 



Verrill. Invert. Au. Vineyard Sd., p. 596. 

 Webster. Annel. Chajt., Provincetowu, p. 724. 



Found near Crab Point in mud. 



Aricia rubra Webster. 



Annel. Chajt. Virginian Coast, pp. 53-55, PL ix, Figs. 23,26. 



Found in mud iiats near the laboratory more abundantly than pre- 

 ceding form in 1884 and 1885. 



SCOLOPLOS CErsted. 

 Scoloplos robustus Verrill. 



Anthoetoma robustum Verrill. Invert. Au. Vineyard Sd., pp. 343,597, 598, PI. xiv, 

 Fig. 76. Note ou Nat. Hist, of Fort Macon (Cones and Yarrow), No. 5. ^ Proc. 

 Acad. Nat. Sci. Phila., 1«7B, pp. 299,300. 



Anthostonut ruhustum Webster. Annel. Cliajt. Virginian Coast, p. 58. 



Scoloplos robustus Verrill. New England Annelida, Pt. i, p. 267. 



Scoloplos rabustus Webster. Annel. Cli;et., Provincetowu, p. 724. 



Many were dug from muddy sand. 



