gg 



LEPTODORA HYALINA. 



females produce summer ova which develope into adults, and produce 

 other summer ova, and so on ; males do not appear until the autumn, 

 and even then are much scarcer than the females. 



At the end of his paper Weismann gives a list of all the localities in 

 which Leptodora had been observed up to the date of his paper, 1874. 

 The first specimens were found by Focke in 1844 in the town moat of 

 Bremen, which is described as being clear water more than 100 feet 

 wide, and moderately deep. Lilljeborg found it in Sweden in 1860. 

 The males were first discovered by Miiller in 1867 in Danish lakes, and 

 in Lakes Geneva and Constance. In 1868 Wagner found it in a Russian 

 lake near Kasan, and, ignorant of its previous discovery, re-named it 

 Hyalosoma dux. It has also occui*red in Lake Maggiore, in Italy, but 

 according to Weismann is not found in Lake Zurich, nor in the small 

 lakes near Lake Constance. 



The above paper suggests several points well worthy the attention 

 of our local naturalists during the present and ensuing months. The 

 occurrence of the Nauplius form is of extreme interest, as an isolated 

 instance among Cladocera ; while the retention by the spring brood of 

 the Nauplius eye affords a ready means of recognising them in their 

 later stages. It will be very important to ascei'tain whether any of this 

 spring brood develope into males, i.e., whether any males are met 

 with possessing the Nauplius eye. Any direct confirmation of the 

 parthenogenetic nature of the summer ova would be also very valuable. 



A point which I would ask any one to determine who has the 

 opportunity of observing a living Leptodora, is the nature of the process 

 of respiration. This will probably be found to be effected, as in Cyclops 

 and other Entomostraca, by means of rhythmical contractions of the 

 terminal dilated portion of the alimentary canal ; water being alternately 

 sucked into and ejected from this dilated portion. The arrangement of 

 the muscular system strongly suggests that this is the real mode of 

 respiration, a point which would probably be settled by a few minutes' 

 observation of a healthy specimen. 



THE FUNGI OF OUR DWELLING HOUSES. 



BY WILLIAM PHILLIPS, F.L.S. 



(Continued from page 38.) 



The next twenty-three species in our list (14 — 36, to which 44 and 46 

 may be added) comprise those which are known as microscopic fungi, 

 buing so minute that they require a magnifying glass to see any of the 

 details of their structure. They may be none the less formidable, how- 

 ever, in their effects on health. When it is remembered that the potato 

 disease, Peronospora infestans, the hollyhock disease, Puecinia malvacearum, 

 the coffee disease, Hemileia vastatrix, together with many others that may 

 be mentioned, are all microscopic fungi, it will be admitted that mere 



