MINERALOGY. 



i47 



upon one host, when the dead individ- 

 uals produce the scumlike appearance 

 noticed by me. The semi-parasitic 

 stage is usually during the winter 

 months. 



This is the only species of the large 

 order that inclines to parasitism and 

 is the smallest in regard to size. None 

 of the species are harmful to fishes, 

 some being' terrestial, others fresh- 



water and a very few marine in habit. 

 In one of my tanks a number of 

 wild snails, Physa heterostropha, had 

 made themselves uninvited inmates, 

 and I found that they were also in- 

 fested by this microscopic worm. I 

 later found that young goldfish fry ate 

 these worms greedily. This is the first 

 reported instance of their occurrence in 

 the vicinity of Philadelphia. 



^■^•^.^•^.^•^.v-^.^->.x-^.%'^.^ , ^.x , ^.^y.x'^.v'^.v , ^.v^.^ , ^.^'^.% , ^.v^.v#.^ , ^.x,'^.x, , i».^'#.>>v.x'^.xr^.% - ^.^y.^ , ^.i 



^wiyiy ipyiyipywiyiywiyiyyywww yiyw 



r 



rOcOOOOOQOCOcCCODCDCCOOOOOOCI 



DO0CXXo qJ Q0C P e>30CXXXCO00O0O3OCr jO OC^ 



MINERALOGY 





Address all correspondence to Arthur Chamberlain, Editor, 56 Hamilton Place, New York City 



A Cuban Cave. 



Caves have a fascination not only 

 for mineralogists and nature students 

 but for almost everybody. 



The picture of Alorro Castle is in- 



teresting not only for its historical in- 

 terest but because it shows at its base 

 a cave being worn out of the coral reefs 

 which form its foundation. 



The second picture, although it rep- 



MORRO CASTLE, SANTIAGO DE CUBA, SHOWING SEA CAVE NOW FORMING 



UNDERNEATH 

 Photograph by Capt. Jos. Priest. 



