462 General Notes. 
Molluses. These glandular pouches empty into the main lumen by 
narrow ducts, while delicate canals, following a contorted. course, 
extend to the periphery of the organ and terminate by ciliated fun- 
nels in the body cavity ina manner which recalls the nephrostomes 
of segmented animals. The excretory duct runs towards the aboral 
surface, and beneath the stone canal forms a narrow duct, both stone 
canal and ureter uniting in a common collecting vescicle which 
empties through the madreporic canals. : 
Lire History or Harr-Worms.—In a recent paper on the 
hair worms L. Camerano discusses several points in connection with 
these forms. He thinks that the same species may occur in differ- 
ent hosts, the filiform condition being found only in insects. Man 
may be occasionally a host for some of the laryal stages. The cycle 
of the individual is as follows: The eggs, which are laid freely in 
the water, hatch out larvee which swim freely and then obtain en- 
trance to a host when they become encysted and undergo a meta- 
morphosis. The metamorphosis results in the young, filiform larve 
which grows directly into the adult, with sexual organs developed. 
This lives freely in the water where copulation takes place and the 
eggs are laid. Some strictures upon the account given by Camer- 
ano may be found in the Zoologisches Anzeiger for 1888, p. 70. 
Villot there states that some of Camerano’s species are in reality 
immature forms. 
THE ORIGIN OF SEGMENTAL Oreans.—M. F. E. Beddard 
(Q. J. M.S., 1888) discusses the structure of the nephridia in Acan- 
thodrilus and Perichæta. In each of these genera there are several 
segmental organs to each segment, there being in Acanthodrilus 
over a hundred apertures in a segment. The glandular part of the 
system varies much from the typical condition of nephridia in other 
respects. In Acanthodrilus the inner openings of the tuft-like 
nephridia were not found, while the excretory ducts of the eight or 
more organs in each segment were branched, each branch communi- 
cating with a nephridiopore. In Perichæta the case is even more 
complicated. The tubules were not observed to branch in the body 
wall, but in the body cavity the nephridial system forms a con- 
tinuous,network passing through the dissepiments from one seg- 
ment to another, while the systems of the right and left side of the 
body also communicate with each other. Internal funnels were not 
found. Beddard reviews the opinions advanced by various natural- 
ists as to the phylogemy of the nephridial system of the anneli 
and thinks that the new facts which he adduces favor the view that 
the annelid excretory system is directly traceable to that of the 
Plathelminthes. He, however, differs from Lang in his theory 
that he does not regard the longitudinal duct of many annelids as 1n 
any way homologous with that of the Plathelminthes, but, m 
the light of Wilson’s researches, as an entirely different structure. 
