536 Miscellanea Zoolvgica. 
the tail, of an olive or yellowish colour, the latter tint most predo- 
minant in front, which is marked with a black spot of a quadrangu- 
lar form, and 4 eyes placed nearly in a square. It was in this 
species that the structure peculiar to the genus was most easily to 
be traced. 
5. N. ptilckra, linear-elliptical * of a flesh-red colour, with a se- 
ries of scarlet spots along each side, or of a uniform aurora- 
red ; eyes numerous, unequal. Plate XVII. Fig. 6. 
HAB. Amongst corallines, and in old shells, &c., in deep water. 
Coast of Berwickshire, frequent. 
Body about an inch in length, and two lines in breadth, compres- 
sed, narrow, elliptical, the front marked with numerous black specks, 
irregularly arranged and visible with the naked eye. Many speci- 
mens are of a uniform aurora-red colour, considerably paler on the 
ventral aspect> while others are beautifully marked along each side 
with a series of large scarlet spots ; the former are perhaps males, 
or more probably individuals in a barren condition, while the others 
seem to be full of mature ova, for an examination of the spots through 
the microscope shows that they are produced by clusters of oviform 
bodies lying in the interstices of the ccecal appendages. 
This and the first species contrast remarkably in their form, and 
show the extremes to which this character is subject. The structure 
of the stomach is like that of its congeners, excepting in there being 
five or six spines on each side of it, instead of three, which is the 
usual number. Immediately under the hearts, we observe a large, 
somewhat muscular viscus, apparently hollow, and lying in the course 
of the intestine, but apparently unconnected with it, for in the indi- 
vidual which served for our figure, the intestine had been extruded 
from the body, and entirely expelled by the contortions of the worm 
produced by impure sea-water. Of its office and nature I ean offer 
no opinion, but I may remark that in all the species a greater dus- 
kiness in its site shows that a similar organ exists iri all. 
* * Alimentary canal apparently homogeneous throughout. Sufo- 
genus, BORLASIA * 
6. N. olivacea, of a dark olive colour ; eyes four, placed in a 
square. Plate XVIII. Fig. 1. 
* A name given by Oken to the Linens of Sowerby, co-equal therefore with 
the Nemertes of Cuvier, equally unnecessary, and as originally applied altogether 
inadmissible. Because it commemorates a worthy naturalist, Dr William Bor- 
lase, author of the History of Cornwall, I rejoice in being able to affix it to a 
group hitherto uncharacterized. 
