BIOLOGY AND ZOOLOGY 131 



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sporoblasts that are formed turns into a spore capable of passing to a new host. The 

 symptoms of the disease in the bee are general ill-health, inability to fly, distention 

 of the abdomen, and dry dysentery. Hives, honey, comb and pollen all may become 

 contaminated with the spores, and the only mode of combatting the disease is com- 

 plete destruction of the infected stocks. Dead bees, old combs and hives must be 

 burnt. Warm weather is favourable to the bees, and cold and rainy seasons to the 

 parasite. It seems to be the case that individual bees may become accustomed to 

 the presence of the parasite and so form permanent reservoirs of the disease. Micro- 

 scopic examination is the only method of being certain in the case of weakly or sus- 

 picious stocks. The parasite probably lives through the winter in hibernating bees, 

 and there is no evidence of such hereditary infection as occurs in the case of- the allied 

 parasite of silkworms (Nosema bombycis). 



For if era (Sponges). 



Most of the new work in this group (see E. B. xxv, 715 ei seq.) is too technical 

 for summary here, consisting of descriptions of new species, details as to geographical 

 distribution, discussions of the minute anatomy, mode of origin and classification of 

 the spicules, nature of the reproductive cells and structure of the tissues. H. F. Moore 

 has published (in the Bulletin of the American Bureau of Fisheries, Vol. xxviii) two 

 important economic memoirs. He shows that the Mediterranean fisheries still pro- 

 duce over half in value of the world's supply of sponges, but that the newer fisheries 

 of the American coast produce by far the largest quantity, although a predominance 

 of the lower priced kinds reduces the value to about one-third of that of the Mediter- 

 ranean fisheries. All known and exploited sponge-beds, however, throughout the 

 world, are showing more or less marked indications of depletion, and in some cases, 

 especially in Florida, there has been a conspicuous falling off in the product under 

 average conditions. This is due more to the intensity of the fishing, than to the taking 

 of small sponges or to improper methods that could be suppressed. The demand is 

 outrunning the supply; prices are rising, and the beds are being fished as they have 

 never been before. Moore thinks that we must look to the development of sponge 

 culture in territorial and extra-territorial waters as the chief hope for future progress. 

 Experiments made under the direction of the Commissioner of Fisheries showed that 

 the method of grafting superior varieties on inferior stocks failed in practice, the graft 

 and the stock growing equally by simple processes of regeneration. Raising new 

 sponges from eggs may be practical in future, but the most successful commercial process 

 appears to be a simple propagation from cuttings. Sponges obtained in commercial 

 fishing, that are too small or too badly shaped to be valuable, are reserved for propa- 

 gation. The rather elaborate method, suggested by Dr. H. V. Wilson, of inducing the 

 formation of degenerate bodies, which, on separation, grow up into little sponges, 

 has been replaced by simply cutting up the sponges into pieces. From 100 to 120 

 " plants," each readily capable of independent growth, were obtained by this method 

 from a six-inch sponge, but in practice it was found more economical to divide the 

 mother sponge into a smaller number of larger pieces, each about two by three inches. 

 The mortality was smaller and the rate of growth greater in these larger cuttings. 

 The cuttings are attached to concrete disks by lead-cased iron wires. Assuming 

 a mortality of about 20 per cent, the net value, at the end of four years from the date 

 of planting, was ascertained to be about four times the cost of planting, and it was 

 estimated that an initial outlay of about 225 dollars art acre would yield about 200 

 dollars per annum. The calculations were based on actual experiments and Moore 

 believes them to be conservative* ' 



. Coelentera. 



The vast bulk of new literature published on the Coelentera (see E. B. vi, 640 

 et seq.) does not contain much of outstanding interest. The most notable publication 

 Is A. G. Mayer's great monograph on the Medusae of the world, consisting of three 



