42 



THE AMERICAN MONTHLY 



[March, 



atilis. I subsequently found two 

 other specimens, one from Bear creek, 

 Benton Co., Iowa, and another in the 

 Calumet creek, i6 miles south of 

 Chicago, having the same interesting 

 peculiarity. 



Although the skeleton spicules and 

 statoblasts of these forms differ widely 

 from each other, yet the arrangement 

 and form of the birotulate spicules 

 appear similar. After this discovery 

 I immediately searched the literature 

 at hand on the subject, but can find 

 no reference nor the remotest hint at 

 anything of the kind. I wrote to 

 Mr. Potts of Philadelphia, who is 

 good authority on fresh-water spon- 

 ges. He kindly forwarded to me a 

 few statoblasts of a sponge sent to him 

 by Mr. Carter two years ago, which, 

 he considers, show the same arrange- 

 ment, although, as it had never been 

 described nor figured, he thought it 

 should be. This sponge is the Spon- 

 gilla Afey en i of Carter , lately merged 

 by him with the Meyenia Jiuviatilis. 

 It was discovered in Bombay, India, 

 and described by Mr. Carter with oth- 

 ers discovered by him at that place in 

 1849. Bowerbank notices the sponge 

 in his first volume of " British Spon- 

 giadae," pages 136, 137, and takes 

 issue with Mr. Carter's remarks on 

 the construction of the walls of the 

 statoblast. Evidently at that time 

 neither of these gentlemen had noticed 

 the serial character of the birotulates 

 in the wall of the statoblasts. 



Since the above was handed to the 

 editor for publication I have received, 

 through the further kindness of Mr. 

 Potts, a pamphlet describing and fig- 

 uring a similar serial arrangen:ient of 

 the birotulates by Dr. Franz Vejdov- 

 sky, of Prague, and also a line from 

 Mr. Carter, of England, stating that 

 Dr. Vejdovsky's paper translated, 

 with remarks by himself, would be 

 published in the February number of 

 Ann. Mag. Nat. History. In a 

 future paper to the Journal I hope 

 to figure and describe the three Amer- 

 ican species found by myself. 



Buffalo, N. Y., Jan. 8th, 1884. 



Mr. Zeiitmayer's Nose-piece. 



Last month a reference was made to 

 a new nose-piece devised by Mr. J. 

 Zentmayer. It is illustrated in fig. 1 1 . 

 It may be of inter- 

 est to briefly indi- 

 cate how the plan 

 originated, as we 

 have the account 

 in a private letter 

 from Mr. Zent- 

 mayer. He writes 

 s u b s t antially as 

 follows: "The 

 principle of at- 

 taching by partly 

 removed threads of 

 ^*°- ^'- screws and nuts is 



old and was used years ago on breech- 

 loaders in Germany, later for drill 

 chucks, and a gentleman in this city 

 years ago attached his objectives by 

 this means. I thought the matter 

 over, but came to the conclusion that 

 it was useless to adopt that method 

 unless all the prominent manufacturers 

 would agree to cut the screw-threads 

 of objectives and nut in the same rela- 

 tion. Seeing the difficulty of estab- 

 lishing such a relation I dropped it, 

 but not without thinking seriously to 

 adopt it for such stands as were fur- 

 nished w^ith my own objectives. * * * 

 I dropped the matter until I saw the 

 ' facility ' nose-piece and the adapta- 

 tion of a collar to the objective. Thus 

 the difficulty was solved. By means 

 of the collar I can manufacture a nose- 

 piece and collar for any objective 

 without having either at hand." 



The plan of cutting away the screw- 

 thread of the objective itself which 

 Mr. Zentmayer at first proposed, is 

 now carried out in England by one 

 manufacturer, Mr. Swift. It is an 

 old plan, which has never found 

 much favor for some quite unaccovmt- 

 able reason. It will be seen from the 

 illustration that the plan adopted by 

 Mr. Zentmayer is to put a small col- 

 lar on the objective and cut away 

 opposite quarters of the threads of 

 that collar, leaving the original thread 

 on the objective intact. The adapter, 



