ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 723 
The definite nervous system is the direct descendant of the arrange- 
ment which obtains in the Turbellaria, but the whole larval system is a 
modification of a still older, primitively diffuse, subcutaneous plexus of 
nerve-cells. Similarly, the ciliated rings have not the significance which 
is so frequently attributed to them, but, like the larval form itself, 
are a secondary peculiarity necessary to a pelagic mode of life. 
Although the setal apparatus is characteristic of Annelids, there aro 
in the Turbellaria similar though superficially placed dermal structures, 
as, for example, in the Enantia spinifera described by Graff. The true 
chaetopodia may have been derived from such primitively irregularly 
arranged dermal weapons. The cephalic tentacles and trunk cirri appear 
to be outgrowths of specially sensitive parts of the integument, the 
entrance of blood-vessels into which would give rise to gills. 
The conception of Annelid ancestry held by the author has a distinct 
bearing on the morphology of the mesoderm. If the peritoneal sacs of 
Annelids, with all their derivates, are to be derived from the gonads of 
their ancestors, then the secondary or coelomatic mesoderm of all 
Metazoa that possess it must have the primitive significance of a gonidial 
tissue. The primitive gonad-cells formed the rudiments of the secondary 
or coelomatic mesoderm, and these do not really belong to either of the 
two primary germinal layers, but are, for a time, intercalated between 
the elements of one or other layer, at the beginning of the ontogenetic 
development of the Metazoa. The author does not regard the embryonic 
mesenchym as a single structure, but rather as the sum of the undif- 
ferentiated rudiments of various organs and tissues, which were primi- 
tively quite independent of one another. 
Australian Earthworms.* — In the sixth of his communications on 
Australian earthworms Mr. J. J. Fletcher describes eight new species, 
treats a number of small perichaete worms as varieties of species pre- 
viously described, and gives further information as to four known species. 
As in earlier papers, the question of generic distinctions is postponed 
for the present. With Cryptodrilus are associated fasciatus, with a 
robust body transversely striped ; Smithi, in which there is an exag- 
gerated condition of the dorsal situation of the outer couple of setae of 
each side, Tryoni , semicindus, and simulans ; the affinities of the last two 
are not quite clear. Acanthodrilus Macleayi is not more than 27 mm. 
long ; the new species associated with Perichseta are called macquariensis 
and terrse-reginse. Two new varieties of Cryptodrilus saccarius are 
described. 
New Genus of Eudrilidse.f — Mr. F. E. Beddard has a preliminary 
note on a new genus of Eudrilidae, which he calls Hyperiodrilus. It 
comes from West Africa, and is most nearly allied to but distinct from 
Stuhlmannia. The setae are in couples, but the dorsal are closely ap- 
proximated, while those of the ventral couple are far apart. There is a 
protrusible penis, which is connected by two grooves with two prominent 
papillae. The most interesting organs from a structural point of view 
are the generative. As in Teleudrilus, the funnels of the four vasa 
deferentia lie in the interior of the sperm-sacs ; the ducts open into a 
* Proc. Linn. Soc. N.S.W., iv. (1890) pp. 987-1019. 
f Zool. Anzeig., xiii. (1890) pp. 561-3. 
