MINUTE ANATOMY OF MEDITERRANEAN NEMERTEANS, 255 
cells being like those of the ganglia, tinged with hemo- 
globin. 
In Drepanophorus (n. gen.) the position of the nerve-trunks 
reminds one of the genus Oerstedia (Quatref.), as they lie 
against the ventral wall of the body cavity, and have conside- 
rably approached the median axis of the animal. The state- 
ment of Mr. MacIntosh as to the position of the nerve-trunks 
in the Meckelian type, viz., between the circular and the inner 
longitudinal muscular coats (‘ ‘Transactions of the Royal 
Society of Edinburgh’) was confirmed in none of the numerous 
Mediterranean representatives of that genus, who all carried 
the nerve-trunks outside the circular layer. 
The Cephalic Furrows, so conspicuous in the larger Mec- 
kelian species, often less distinct in the enoplan forms, are 
universally in connection with the cephalic sacs, which latter 
seem to take a different position in the Enopla and in the 
Anopla. ‘The shape of these organs in the armed Drepano- 
phorus resembled that of the “side organs” in Keferstein’s 
Borlasia splendida, though they were situated more behind 
the gangha. ‘They were connected with these by four com- 
missures, which passed uninterruptedly from the ganglionic 
texture into that of the cephalic sac. Furthermore, they 
showed pigmented spots and a small knotty elevation on one 
side, which reached into the cephalic furrow. I could not 
make out distinctly whether an internal ciliated canal was 
present or not. In other enoplan species the position of the 
“side organs” is generally in front of the ganglia, with 
which they are connected by only one commissure. 
The Borlasian subdvision shows a rather different distribu- 
tion of the parts. ‘The cephalic sacs lie behind the ganglia ; 
they have a spherical or pyriform shape, and generally a 
distinctly visible internal ciliated canal, corresponding with 
the cephalic furrows and permitting the sea-water to enter 
freely. In their posterior portion they carry translucent 
globules figured successively by Van Beneden, MacIntosh, 
and myself. 
The structure of the cephalic sacs in this subdivision was 
studied by me im several series of sections through them 
and through the ganglia, a reconstruction of the whole 
being in this way obtained. It then became evident that 
their constitution entirely corresponded with and immediately 
passed into that of the ganglionic lobes. Not only, as 1 
remarked above, do the central bundles pass from the one 
into the other, but the enclosing layer of nerve-cells is quite 
as thick and conspicuous ; the central ciliated canal can be 
traced in these transverse sections with perfect accuracy. It 
VOL, XV.-—NEW SER, s 
