628 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



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

 (A. Agassiz). In sand between tides. 



A reexamination of living specimens of the 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.) 



Nemertes 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. Yery com- 

 mon under stones, between tides. 



Nemertes viridis Diesing. _ 



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

 naria viridis Muller, Zool.Dan. Prodromus, 2684, 1776 (t. Fab.) ; Fabricius, Fauna 

 Grosnlandica, p. 324, 1780. Notospermns viridis Diesing, Syst. Helminth, vol. i, 

 p. 260, 1850. Nemertes 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, PI. 2 b , fig. 1, 1865. Nemertes obscura Desor, Boston Journal 

 of Natural History, vol. vi, pp. 1 to 12, Plates 1 and 2, 1848. Folia obscura 

 Girard iu Stimpson's Marine Invertebrata of Grand Mauan, 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 mm ; 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 mm 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 fossae of the 

 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 

 fossae ; 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 fossae, which are short and extend 

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

 small and round, situated slightly behind the posterior euds of the lat- 

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



