180 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the sperm-sacs is unsatisfactory, owing to the contradictory statements 
that have been made regarding them. Mr. Beddard finds that the testes 
are largest in individuals that are not sexually mature ; in them they 
form a bunch of divergent finger-like processes attached to both sides of 
the septum ; and the bunches are paired. In P. verrucosus there were 
two pairs of testes, but there may be individual variation in the number. 
The author agrees with Michaelsen in denying the presence of sperm- 
sacs, and he suggests that the large size of the testes and the stout 
peritoneal investment render their development unnecessary. 
Pachydrilus subterraneus.* — Prof. F. Vejdovsky gives a description 
of this new species, which has been found both at Prague and Lille. It 
is about 20 mm. long, is of a bright red colour, and is almost constantly 
in movement in the water in which it dwells. 
)8. Nematlielniintlies, 
Respiration of Entozoic Worms.!— Herr G. Bunge, who has already 
shown that Ascaris mystax, which is found in the intestines of the cat, 
will live four or five days in media quite free from oxygen, has continued 
his investigations with other Nematodes. A. acus, from the pike, which 
has no respiratory apparatus, was found to live from four to six days, 
and exhibit movements in similar media. 
In the ultimate respiratory processes of these animals there must 
be a formation of energetic reducing substances (nascent hydrogen and 
easily oxidizable organic matter) which unite with one atom of the 
oxygen-molecule, even to a greater extent than in animals which breathe 
oxygen. Larger varieties of Ascaris were also examined. A. megalocephala 
of the horse lived, however, only for two days ; A. lumbricoides of the 
pig, from four to seven. The gas given off was found to bo not only 
free from hydrogen, but from other reducing substances also. 
Developmental Cycle of a Filaria of the Dog.J — Prof. B. Grassi 
describes the adult form of Filaria recondita Grassi, a specimen of 'which 
was examined by him and also by Dr. S. Calandruccio. The specimen, 
the only one obtainable, was a not quite mature female, and was found 
rolled up but unencapsuled on the fatty tissue close to the hylus of the 
right kidney. It is about 3 cm. long and 178 /x broad. 
It would seem that this Filaria passes through four larval stages. In 
the first of these it exists in the blood of the dog, from which it is 
sucked out by the flea {Pnlex serraliceps^. The second stage is passed 
in the cells of the fat-bodies, the principal change being that it increases 
in size very much, the general shape being retained. In the third stage 
it not only increases in size, but the various parts and organs become 
more highly differentiated. In the fourth stage it exists in the en- 
capsuled condition, being found rolled up within the cell of the fat- 
bodies. 
Inoculation experiments with the object of infecting dogs by means 
of fleas were without success. This failure is ascribed to the fact that 
the authors were obliged to use larvae in the third stage of development, 
* Kev. Biol, du Nord de la France, i. (1888-9) 3 pp. (sep. copy) 1 pi. 
t Zeit. Physiol. Ohem., xiv., pp. 318-24. See Journ. Chem. Soc., i890, p. 274. 
X Centralbl. f. Bakteriol. u. Parasitenk., vii. (1890) pp. 18-26 (17 figs.). 
