RANDOM NOTES ON NATURAL HISTORY. 



Warren and Franconia, N. H., and Sebago, 

 Me. It will rank as one of our most nota- 

 ble buildings, built with novel material, and 

 presenting an object for much study. 



W. S. Beekman. 



Genera of Pteropoda from NarraganseLt 

 Bay. 



Precious Opal. 



Since the time Pliny accuratel}' described 

 bis opalus, to the present day, this hand- 

 some mineral has been esteemed a gem, 

 though not always assigned the same rank ; 

 for fashion, in its capricious vagaries, dis- 

 places and reinstates it in favor at irregular 

 intervals. Its innate beauty* so happily 

 characterized in the lines, 



" Milky opals that gleam and shine 

 Like sullen fires through a pallid mist," 



coupled with the fact that it is perhaps the 

 onlj- stone really defying imitation, has en- 

 abled it to eventuallj- hold its own. The 

 high rank awarded it in ancient times wag 

 undoubtedly largely due to the comparative 

 ease with which it could be worked, and 

 also to the fact that unlike all other precious 

 stones much of its beauty was revealed and 

 available without an3' labor. The strange 

 popular belief of modern da^'s that opal is 

 an unluck}^ stone to the wearer, appears to 

 be directl}' traceable to Sir Walter Scott's 

 romance of Anne of Geierstein. In its 

 usual occurrence in seams or veins in por- 

 phyry and igneous rocks, it is plainly an 

 infiltration of gelatinous silica (silica in the 

 colloid state), often mixed with considera- 

 ble crystalloid silica, and retaining more or 

 less of the originall}' combined water. In- 

 deed, precious opal proper seems, as a rule, 

 to contain more water than the other vari- 

 eties. Until within the past few 3'ears the 

 greater part of the material for commerce 

 has been of Hungarian and Mexican origin, 

 but a new source of supplj' has been discov- 

 ered in Queensland. In the variety from 

 this localit}', which may in some respects be 

 considered unique, the usual fiery reflections 

 are displaced partly, or even entirely-, by 

 the most splendent metallic hues — greens 

 and blues of every conceivable shade — the 

 individual colors in some instances being 

 arranged in more or less distinctly defined 

 bands or zones, or again imperceptil)ly melt- 

 ing into each other and vying with tlie plu- 

 mage of humming-birds in magnificence. 

 — F. W. S.i in WarcVs Natural Science 

 Bulletin. 



Editors of Random Notes : 



My attention has been called to a l)iief 

 notice in your magazine of the Pteropoda, 

 or " Sea-butterflies," forming a part of tlie 

 shell-bearing Mollusca of Rhode Island. I 

 am able to add to that notice a few genera, 

 some of which have not previously been 

 recorded, from this locality. All of these 

 and several more have been collected by 

 the United States Fish Commission and have 

 been mentioned and described by Professor 

 Verrill, but in man^' instances the localities 

 from which the specimens collected by the 

 Commission were obtained are outside of the 

 limits of Rhode Island waters, while all the 

 Pteropods here recorded were found at 

 Newport, a few hundred feet from the shore. 

 The value of the present list is simplj- as 

 a contribution to the local distribution of 

 these animals. A description of two young 

 forms of a naked Pteropod is appended. 

 I have in preparation a more extended ac- 

 count of the anatomy and development of 

 New England Pteropoda, where other stages 

 in the growth of the last mentioned genus 

 (Clione) will be described. 



Of the shell-bearing Pteropoda or Tiieco- 

 SOMATA, the following genera occur in Nar- 

 ragansett Bay : 



Cavolina. 



Cynibulia. 



Styliola. 



Spir talis. 

 The naked bodied Pteropoda or Gymnos- 

 OMATA are represented by at least one genus 

 and species (Cliotic papiUonaci a) , two lar- 

 val forms of which are here described for 

 the first time. 

 Cavolina. 



The genus Cavolina is found every sum- 

 mer at Newport. The species resembles 

 closel}' C. tridentata Gray, and is generally 

 captured in the night-time. 

 Cf/nibi(lia. 



The " boat-shaped " shell of the genus 

 Ci/mbuUa was found in 1880 at Newport. 

 This beautiful genus, one of the largest of 

 Mediterranean Ptei-opoda, is easilv recog- 

 nized by its slipper-shaped, transparent, 

 cartilaginous shell,with notched and serrated 

 edges. The single specimen was dead and 



