334 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [623] 



Carolina (Girard). Newport, Khode Island, to Beverly, Massachusetts 

 (A. Agassiz). In sand between tides. 



A reexamination of living specimens of tlie southern form will be 



necessary before their identity with the northern one can be positively 



established. I am unable to separate them with preserved specimens. 



See page 351 ; also American Journal of Science, ser. 3, vol. v, p. 235.) 



XEMERTES SOCIALIS Leidy. (p. 324.) 



Marine Invert. Fauna of Rhode Island and New Jersey, p. 11 (143), 1855. 



Great Egg Harbor to New Haven and Vineyard Sound. Very com 

 mon under stones, between tides. 



NEMERTES VIRIDIS Diesing. 



Sitzungsberichte der kais. Akad. der Wissenschaften, vol. xlv, p. 305, 1862. Pla- 

 nariaviridis Miiller, Zool.Dan. Prodromus, 2684, 1776 (t. Fab.) ; Fabricius, Fauna 

 Groenlandica, p. 324, 1780. Notospermua viridis Diesing, Syst. Helminth, vol. i, 

 p. 260, 1850. Xemcrtes olivacea Johnston, Mag. of Zoology and Botany, vol. i, 

 p. 536, PI. 18, fig. 1. Borlasia olivacea Johnston, Catalogue British Non-para 

 sitical Worms, p. 21, PL 2 b , fig. 1, 18G5. Nemertes obscura Desor, Boston Journal 

 of Natural History, vol. vi, pp. 1 to 12, Plates 1 and 2, 1848. Polia olscura 

 Girard in Stimpson s Marine Invertebrata of Grand Man an, p. 28, 1853. 



Body very changeable in form ; in full extension long and slender, 

 sub-terete, tapering toward both ends, the length being sometimes 150 mm 

 to 200 mm , while the diameter is 2 mm to 3 inm in contraction the body 

 becomes much shorter and stouter, more or less flattened, and obtuse at 

 the ends, large specimens often being only 30 mm or 40 11UU long and 4 mm to 

 5 mm broad. The head is flattened, more or less bluntly rounded, and is 

 furnished with a row of small dark ocelli on each side, which vary in 

 number and size according to the age, the large specimens often having 

 six or eight on each side, while the small ones have but three or four, and 

 the very young ones have only a single pair. The lateral fossa3 of the %i 

 head are long and deep, in the form of slits, and extend well forward to 

 near the terminal pore. The latter in some states of contraction appears 

 like a slight vertical slit or notch, but at other times appears circular; the 

 proboscis is long, slender toward the base, clavate toward the end, the 

 terminal portion transversely wrinkled. The ventral opening or mouth 

 is situated opposite to or a little behind the posterior ends of the lateral 

 fossa? $ it is ordinarily small and elliptical, with a distinct lighter colored 

 border, but is capable of great dilation when the creature is engaged in 

 swallowing some annelid nearly as large as itself. 



In alcoholic specimens the body is usually thickened and rounded 

 anteriorly, more slender and somewhat flattened farther back, often acute 

 at the posterior end; head obtusely rounded or sub-truncate, with a 

 small terminal pore and two lateral fossa3, which are short and extend 

 forward very near to the terminal pore; ventral opening or mouth 

 small and round, situated slightly behind the posterior ends of the lat 

 eral fossa? : ocelli not apparent. The color, when living, is very variable, 



