586 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
base through 180°. The author describes in detail the calyx and the 
crown of tentacles ; what is ordinarily known as the epistome is nothing 
more than that region of the floor of the lophophore which fuses with 
the upper edge of the buccal orifice. In some points Dr. Frouho’s 
investigations enable him to confirm the results of Harmer ; in the case 
of the nephridia he is able to make some additions to our knowledge. 
He regards the nephridium of Loxosoma annelidicola as being a group 
of two or three excretory cells placed in a definite space in the midst of 
the parenchyma ; in this space there is also a vibratile area (the true struc- 
ture of which is still unknown), which opens to the exterior by a ciliated 
canal. The space inclosing the excretory cells communicates with the 
exterior ; the products excreted by these cells fall into the space and are 
carried outwards by cilia. The author cannot agree with Foettinger 
in thinking that there is any intracellular canal in these cells. 
After some observations on budding, attention is drawn to the 
adaptation of Loxosoma annelidicola to its habitat ; the Clymenid on 
which it lives is lodged in a thick and solid tube, between which and the 
worm there is but little space ; we can understand, therefore, that in its 
normal position the Loxosoma is sharply inclined on its peduncle, while 
its calyx is extended transversely as if it had been flattened between the 
worm and its tube. As the Clymenid moves up and down its tube, it 
swells some of its rings ; to avoid the danger to which it is thus exposed, 
the guest twists itself on its axis ; and we may well suppose that the 
helicoidal muscles of the stalk are specially developed with regard to 
these movements. The Clymenids on which this species of Loxosoma 
has as yet been observed are Nicomache lumbricalis and Petaloprodus 
terricola. 
Characters of Melicertitidae and other Fossil Bryozoa,* — Hr. A. W. 
"W aters calls attention to certain cheilostomatous characters in Melicertites 
and other fossil Bryozoa ; such are the presence of aviculariae, the large 
size of the pores, the plates on the apertures of the zooecia. He urges 
the importance of a thorough comparison of Palaeozoic with Cretaceous 
genera, as the latter form an excellent stepping-stone between the rich 
Carboniferous fauna and the recent. In the Cretaceous Melicertitidae the 
characters are in the main cheilostomatous but some are cyclostomatous, 
while in many Palaeozoic fossils there are important structures similar 
to those in recent Cheilostomata. 
Marine Polyzoa.f — The Eev. T. Hincks continues his “ appendix ’ ’ 
to his “ Contributions towards a General History of the Marine 
Polyzoa ” ; in this new species are described and additions and correc- 
tions made to our existing knowledge. 
Arthropoda. 
Circulatory and Respiratory Organs of 'some Arthropods.* — M. A. 
Schneider has some scattered notes on these organs in Amphipods, 
Arachnids, and Araneids ; the lung of the last has not the chitinous 
envelope which has lately been described as investing it. 
* Ann. and Mag. Nat. Hist., viii. (1891) pp. 48-53 (1 pi.). 
t Tom. cit., pp. 86-93. ♦ Comptes Rendus/cxiii. (1891) pp. 94-5. 
