A. E. Verrill — Marine Nemerteans of Neio England, etc. 407 

 Tetrastemma vermiculus (Quatr.) stimpson. 



Polia vermiculus Quatrefap:es, Ann. des sc. nat., ser. Ill, Zool., vol. vi, p. 214, 184G; 



Voyage en Sicilie, vol. ii, p. 12G, pi. xiv, figs. 12, 13, 1849. 

 Nernertes vermiculus Diesing, Syst. Helm., vol. i, p. 270, 1850. 

 Tetrastemma vermiculus Stimpson, Proc. Acad. Nat. Sci. Philad, vol. ix, p. 1G3 (19), 



1857 ; Diesing, Revis der Turbell., p. 290, 1862. 

 Tetrastemma vermictila Mcintosh, British Annelids. Part I, Nemerteans, p. 169, 



Plate HI, fig. 3, 1873. 

 Tetrastemma vermicuhts Verrill, Notice of Regent Addit. to Mar. Invert., Part I, in 



Proc. National Mus., ii, p. 184, 1879; Check List, 1879. 



Plate xxxiii, figures 11 to lie; plate xxxiv, figures 11, 12; plate xxxt, 



FIGURES 8, 11. 



Body versatile, rather slender in extension, obtuse at both ends; 

 sometimes tapered to the posterior end, but more often of nearly 

 uniform diameter. Ocelli conspicuous, the two pairs i-ather far 

 apart when the head is extended, those on the same side farther 

 separated than those of a single pair, and connected by a dark line 

 of pigment, which is rarely absent. 



Color rather variable; above, often pale yellowish, or pale salmon, 

 or translucent yellowish gray, more or less specked or spotted, espe- 

 cially along the sides, with brown, often leaving a paler, wide, 

 rather indefinite dorsal stripe ; ventral surface and front of head 

 pale. 



Length, in extension, about 20™™; breadth 1""°. Described from 

 life. 



Many specimens taken at Wood's Holl in the mud of Little Hai'- 

 bor, .Tuly 25th, 1881, and August 4th, 1882, varied from dull orange- 

 yellow to bright greenish 3^ellow, more or less covered with specks 

 of brown, especially on the sides, yet not forming a definite dorsal 

 stripe, but with a darker brownish, often indistinct stripe on each 

 side of the head between the eyes. 



Length up to 18 to 20'""'. 



Yoimg — several young specimens of this species were taken 

 together in a tide-pool, in 18*78 (No. 12). 



Body slender, of nearly the same width throughout. Ocelli con- 

 spicuous, the two pairs more widely separated than usual when tlie 

 head is extended ; the front ones a little larger than tlie others. 

 Color translucent pale yellow, bright salmon, and flesh-color, usuallv 

 with a white median spot in front of the anterior ocelli, and some- 

 times, also, with other white specks along the back; frequently an 

 irregular brownish band runs along each side of the back; median 

 line paler. Li many of the specimens a faint longitudinal line of 



