CIRCULATORY APPARATUS OF THE NEMERTEA. 13 
longitudinal and circular layers. And in Cephalotrix, lying 
already within the muscular coats, they go outwards, but do 
not go farther than the midst of the longitudinal layer, where 
they remain. 
Of the vascular system I will here only note one peculiarity, 
viz. that Valencinia has a median dorsal vessel, which is 
absent in the three other genera. 
Carinoma Armandi (MclInt.), Oud., has the following 
external characters: Length to 20 c.m., width that of a stout 
thread (contracted and in spirits 1 mm.). Body cylindrical 
except the flattened head and the also flattened tail, which 
terminates in a long point. The foremost part of the body is 
whitish, the hindmost pale buff and the tail translucent. Eyes 
are absent. 
d. REsuLts OF THE INVESTIGATION. 
1. Cephalotrix linearis (Rathke), Oerst., figs. 1, 19—22. 
The vascular system of Cephalotrix consists in two longi- 
tudinal trunks, which communicate in the tip of the snout and 
in the tail. I had no opportunity of convincing myself of the 
latter fact by personal examination. 
Before the ganglia we find two lacunar spaces, one on each 
side of the proboscidian sheath (fig. 19), which communicate in 
the tip of the snout (fig. 1) by means of an arch above the 
proboscidian sheath. This arch, too, is lacunar, that is to say, 
irregular in shape, and when cut transversally does not show a 
circular or ellipsoidal form. There are, moreover, no muscular 
or other fibrillar walls, though the blood-fluid, as one would be 
inclined to think from the expression lacunar, does not wash 
directly the longitudinal muscular layer, nor even do the 
lacunz present themselves as gaps in the gelatinous tissue 
that fills up the room between the proboscidian sheath and the 
longitudinal muscular coat. On the contrary, though the 
lacune are imbedded in the gelatinous stroma, this is—where 
it forms the lining of the lumen of the lacuna—changed so 
that it absorbs more colouring material than elsewhere farther 
