536 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
Geonemertes agricola (Willemoes-Suhm). 
Tetrastemma agricola Willemoes-Suhm, Ann. mag. nat. hist., vol. 
13, p. 409, pi. 7, fig. 1-3, 1874. 
Tetrastemma agricola Moseley, Notes by a naturalist on the Chal¬ 
lenger, pp. 26, 27. London, 1879. 
Tetrastemma agricola Hubrecht, Challenger reports, vol. 19, p. 
23, 1887. 
JTeonemertes agricola Girard, Ann. sci. nat., zool., ser. 7, vol. 15, 
p. 238, 1893 ; Joubin, Les nemertiens, Fauna Franyaise, Paris, 1893. 
Geonemertes agricola Burger, Fauna und flora des Golfes von 
Neapel, monogr. 22, p. 557, 1895. 
Tetrastemma agricola Verrill, Trans. Connecticut acad. sci., vol. 
11, p. 847, 1901-02. 
Body slender, flattened, of almost uniform width throughout. 
Head when extended somewhat broader than body although not 
distinctly demarcated, widest in the vicinity of the ocelli and nar¬ 
rowing gradually toward tip of snout. After preservation, or when 
contracted, head is continuous with body and of uniform width, 
being sharply truncated anteriorly and often very slightly bilobed 
in front. Esophagus opens into rhynchodaeum immediately in front 
of brain and the latter into a subterminal atrium which is not sharply 
marked off from rhynchodaeum. On each side of atrial, or rhyncho- 
daeal, opening is a rather conspicuous horizontal furrow extending 
backward for some distance on the lateral border of snout. An 
indistinct vertical groove passes through the rhynchodaeal opening in 
preserved specimens. An inconspicuous V-shaped marking or groove 
is situated symmetrically on dorsal side of posterior portion of head 
and extends antero-laterally nearly to ventral surface. When head 
is well extended in life this groove lies between the anterior and 
posterior pairs of ocelli, but after preservation or when head is 
strongly contracted it lies immediately posterior to ocelli. 
Esophageal and intestinal regions of nearly uniform width ; in 
life subcylindrical, but after preservation about one and one half 
times as wide as thick; tapering gradually to narrow posterior 
extremity (pi. 23, figs. 1, 2). When killed in formalin posterior 
portion of body usually coils dorsally like a short watch spring 
while the anterior half of body remains nearly straight. This gives 
