140 THE NAUTILUS. 



PUBLICATIONS BECEIVED. 



Notes on the Victorian SPEcir:s of Bullinus. By Charles 

 Iledley (Records of the Australian Museum, vol. 12, pp. 1-8, 

 pis. 1-2, 1917). The following interesting note preceeds the 

 systematic treatise of the species: "Those fresh-water snails 

 once known in Australia as Physa, but now referred to as 

 Bidlinus, have recently ac(|uired an uni)lea.sant interest. For 

 the spread and nurture of haematura, a severe, painful and 

 incurable complaint has recently been traced to Eg>'ptian 

 representatives of Bullinus. 



"The newly hatched embryo of a Trematode, called Bil- 

 harzia, enters the Bullinus snail and there turns into a sporo- 

 cyst. Then Bilharzid cercariae are discharged from the in- 

 fected snail every day for weeks, more plentifully and con- 

 tinuously in summer. The free-swimming larvae swarm on 

 the surface of the water in search of a victim. Should they 

 fail to find a host within forty-eight hours they must die. A 

 successful parasite enters the human body either by the mouth 

 or through the skin, and proceeds to establish itself in the 

 rectum or bladder. Arrived at maturity, the parasite sheds 

 innumerable hard-shelled eggs. These erode the mucous mem- 

 brane, thus causing internal bleeding, a symptom of the dis- 

 ease. Victims may even die from necrosis of the liver or 

 blockage of portal veins. ' ' 



It is to be presumed if this plague were to be introduced 

 from Africa or Asia, the Australian species of Bullinus would 

 serve as an intermediate host and so transmit it. Previously 

 an Australian Bullinus had been indicated as an intermediate 

 host for the sheep fluke. — C. W. J. 



The Economics of Trochus niloticus. By Charles Hed- 

 ley (The Australian Zoologist, vol. 1, pt. 4, pp. 69-73, pi. 6, 

 1917). A very interesting account of its economic value, dis- 

 tribution, etc. Its dense, firm nacre proves good material for 

 buttons, and during the past six years the demand for Tro- 

 chus by button-makei*s has caused the price to advance from 

 twenty to thirty pounds a ton. The export of Trochus from 

 Queensland in 1916 was 950 tons, worth £23,000. The Philip- 



