ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
195 
forward by the supposition that in Acanthodrilus multiporus the genital 
funnels and a portion at least of the ducts are formed out of nephridia. 
This mode of development confirms the suggestion of the late Prof. 
Balfour that in the Oligochmta the nephridium is broken up into a 
genital and an excretory portion. 
Reproduction of Autolyteae* — M. A. Malaquin has studied the 
formation of the stolons in Autolytus , Myrianida, and Procerastea. Some 
species of Autolytus exhibit merely fission, while in others there is 
fission and budding. In Myrianida there is budding without fission. 
When there is budding the somite which proliferates is the pre-anal in 
Myrianida and certain species of Autolytus ; the anal segment is, from the 
first, too differentiated to take part in the formation of new zoonites. 
The “ formative zoonite ” has no appendages ; it is filled by embryonic 
tissue ; when it exists it gives rise, when there is a free proximal surface, to 
a new head (centrifugal budding), or when the free surface is distal to a 
new pygidium (centripetal budding). If the formative zoonite is in 
contact with a stolon, a pygidium is formed on the dorsal surface ; the 
anal segment plays, so to speak, the part of an isolator ; it separates two 
individualities which are becoming more and more marked. The zone 
of new formation is colourless and transparent : the formative zoonite is 
larger than the zoonites which precede it. On this segment, which is at 
first undivided, there appear two lateral grooves which converge and meet 
on the median line ; the rudiments of feet, cirri, setae, are successively 
differentiated. In Myrianida the author observed a stem of sixty-six 
segments, followed by twenty-nine male stolons, containing about four 
hundred and fifty segments, and thirty actively proliferating zones. 
Reproduction has also been observed in Procerastea Halleziana 
sp. n. ; here the phenomenon of fission is complicated by a median 
budding before the appearance of the head. The proliferating bud only 
gives off segments anteriorly. 
The growth of the stolons is described in Polybostrichus and 
Sacconereis. In the former the formative zoonite immediately gives 
rise to the two most differentiated segments — the segment which buds 
off the head and the pygidium ; the segments next to be formed are 
those which contain the genital organs. The head of Sacconereis is 
formed in the same way as that of Polybostrichus. Dimorphism is much 
more marked in this genus. 
j 3. Nemathelminthes. 
Filariae of Birds. t — Dr. T. L. Bancroft has investigated the hmmat- 
entozoa of Australian birds, and, as he was fortunate enough to find them in 
the Blue-Mountain Parrot, which eats only honey, he was able to trace the 
cycle of changes. This parrot harbours, as most birds do, a blood-sucking 
louse. The author, therefore, believes himself justified in assuming that 
the lice of birds are the intermediate hosts in the life-history of the 
Filarise of birds, and that birds infect themselves by picking lice from 
an infected bird, and afterwards re-infect themselves by picking their 
own lice ; this would account for the immense number of haematentozoa 
* Comptes Rendus, cxi. (1890) pp. 989-91. 
f Proc. Roy. Soc. Queensland, vi. (1889) pp. 58-02. 
o 2 
