62 PERCY SLADEN TRUST EXPEDITION. 
Lastly, with regard to the question of the origin of land-nemerteans—whether they 
have arisen from freshwater forms, as Montgomery * has supposed, or directly from 
marine species. Coe points out that the absence of fresh water in the Bermudas 
suggests a direct marine origin for G. agricola; he also says that it can live in salt 
water but not in fresh. In the matter of marine origin, I agree with Coe. The fresh- 
water streams in the Seychelles are small and abound in torrents. It is difficult to 
conceive how a nemertean could have made its way up to 1500-2000 feet by such a 
Passage. 
EXPLANATION OF PLATE 11. 
bm. = basement membrane. m.l, = longitudinal muscular layer. 
bv. = blood-vessel. m.c. = circular muscular layer. 
c.c. = ciliated canal of cerebral organ. n.c. = cephalic nerves. 
c.or.gl. = gland of cerebral organ. | oc. = eye. 
d.c. = dorsal commissure of brain. @s. = cesophagus. 
d.d.g. = dorsal lobe of dorsal ganglion. ov. = ovary. 
dg. = dorsal ganglion. pr. = proboscis. 
jr. = frontal organ. ps. = proboscis-sheath. 
gl.c. = cephalic glands. rhd. = rhyuchodieun. 
int. = intestine. = iegaRe 
in. = lateral nerve-cord. v.c. = ventral commissure. 
l.n.a. = accessory lateral nerve. vg. = ventral ganglion. 
m. = muscle-fibres. 
Fig. 1. Sketch of preserved specimen. X 3. 
Fig. 2. Transverse section near tip of snout. x 90. 
Pig. 3. Transverse section immediately anterior to the commencement of the brain. x 90. 
Fig. 4. Transverse section through brain-region. x 90. 
Fig. 5. Transverse section through cesophageal region behind the brain but before the commencement 
of the stomach. x 67. 
Fig. 6. Transverse section through about the middle of the animal’s body. x 47. 
ig. 7. Ovary containing a single ovum attached by two wide processes to the follicle-cells. On the 
— 
Fig. 
outer side is to be seen the commencement of the oviduct, which is not yet completely 
formed. x 120. 
* Journ. Morph. vol. ii. (1895). 
