290 Ww. C. M’INTOSH, 
being invariable inthe ENopia. The mouth in the author’s 
figure refers to the cesophageal region. The proboscis will 
probably be found on transverse section to be within a pro- 
boscidian sheath, composed chiefly of external circular (or 
oblique) and internal longitudinal fibres, with the probosci- 
dian corpusculated fluid in its interior. The termination of 
the proboscis, therefore, willnot be attached to the walls of 
the body, but to the interior of the sheath. The sexual dif- 
ferences in the basal portions of the central stylet are most 
interesting, and the author is quite right in observing that 
such sexual differences have not hitherto been observed in 
the Nemerteans, though various varieties occur in the same 
form. The remarks on the habits of the species are also 
valuable. The commensalistic Nemertean alluded to by the 
author at the end of his paper is closely allied to the Nemertes 
carcinophila of Kolliker, and it probably has a similar habit 
of frequenting (in sheaths) the abdominal hairs of female 
crabs. ‘The occurrence of lateral stylet-sacs is noteworthy. 
The plate accompanying the paper is probably diagrammatic, 
and the inversion of the figures, the inversion of the gan- 
glionic commissures, and other imperfections, need not there- 
fore be mentioned. 
In some additional remarks on a hermaphrodite Nemertean 
(Borlasia Kefersteinii) by M. Marion,' he finds that the young 
specimens show a predominance of one sexual element, 
while the older forms have a nearly equal proportion of 
male and female elements. The male reproductive elements 
are developed first, and then the female. He is somewhat 
in doubt about the connection of the ovaries and sperm-sacs 
with surrounding parts—mentioning that they occur without 
order in the general cavity of the body, and that they have 
a short peduncle apparently in connection with the lateral 
vessel. ‘This is scarcely accurate, for the sexual organs 
have no connection with the lateral vessel, the contents find- 
ing exit above the nerve and vessel. He again alludes to 
the spermatozoa being liberated in April into the general 
cavity of the body, another misapprehension, since the pro- 
boscidian canal (cavity of the sheath) and the digestive tract 
are the only general cavities within the body-wall. He 
probably means the region between the body-wall and the 
alimentary canal, but there is no space there, only the 
ovaries and the sperm-sacs. There is nothing new in his 
observations on the young animals. Whether the spermatozoa 
impregnate the ova without passing into the surrounding 
water, or after diffusion through that element, has not been 
ascertained in this form; but the latter would seem very 
1 « Ann. des Se. Nat.,’ 6e sér, Zool., tom. i, pp. 19, &e. 
