ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
397 
this interpretation the male Dicyemids would arise from fertilised ova, 
and the females or nematogens from unfertilised ova. 
The following life-history of Dicyema is suggested. Both the females 
(nematogens) and the males (infusiforms) may migrate from one 
Octopus to another. One or more nematogens probably enter the kidney 
soon after the Octopus is hatched, and multiply psedogenetically till the 
surfaces of the venous appendages are tufted with nematogens. After 
a time parthenogenesis languishes, the germ-cells being no longer able 
to produce vermiform embryos. By this time one or more males from 
some other Octopus find their way into the kidney and discharge their 
spermatozoa, which enter the axial cells of the nematogens and fertilise 
the germ-cells aggregated in the infusorigens. From these cells develop 
the males, which may in turn fertilise either the remaining nematogens 
in the same kidney, or may migrate to other Cephalopods. As in so 
many other cases in the animal and vegetable kingdoms, the males make 
their appearance when the conditions of life become unfavourable, 
namely, after the kidney is well peopled with Dicyemids, and food is 
less abundant. These unfavourable conditions are perhaps still further 
aggravated by changes in the renal metabolism of the Octopus when 
it is about 4 cm. long. 
As to the systematic position of the Dicyemids, their mode of repro- 
duction seems very unlike that of the flat- worms. It seems to Wheeler 
a step backward to place them in a separate sub-kingdom (Mesozoa)-, 
yet their structural and developmental peculiarities entitle them to a 
more independent rank than that of an appendix to the Platyhelminthes. 
Three New Orthonectids.* — MM. Maurice Caullery and Felix Mesnil 
describe three new species of Orthonectids, one of which they regard 
as constituting the type of a new family. The first two species are 
referred to the genus JXhopalura g. n., and of them both males and females 
were found. One, to which the name of JR. MetcJinikovi is giveD, 
occurred in Spio Mariinensis Mesn., the other, R. Julini , occurred 
in Scolelepis fuliginosa. The third form was found in Scoloplos JMulleri 
Rathke, and from thirty infested worms some hundreds of specimens 
were taken. All of these were uniform in appearance and apparently 
females, but close examination showed three testicles in each, proving 
that the form in question is a hermaphrodite. To this form the name of 
Stoechar thrum Giardi g. et sp. n. is given. Besides the hermaphroditism, 
it is characterised by the elongated body consisting of 60-70 rings. In 
JRhopalura Julini the female shows an anterior group of cells, which 
seems to be the rudiment of a testicle. The authors believe that the 
hermaphroditism of Stcecharthrum has been secondarily acquired by the 
female. 
Echinoderma. 
Bermuda Echinoderms.f— Mr. Id. L. Clark reports on a collection 
of eleven species. One of the two Asteroids ( Asterias tenuispina = 
A. atlantica ) is remarkable for the great variation of its arms, which 
may number 4, 5, 6, 7, or 9. In regard to the species of Stichopus , of 
* Comptcs Rcndus, cxxviii. (1899) pp. 457-60. 
f Ann. New York Acad. Sci., xi. (1898) pp. 407-13. 
