September 12, 1913] 



SCIENCE 



363 



mathematics in the University of Calcutta, 

 for the purpose of organizing there a new 

 school of higher mathematics. As the duties 

 of the post require his residence in India only 

 from November to March, it has been ar- 

 ranged that he shall retain his professorship 

 in Liverpool University. 



Mr. Harold Pealixo. Liverpool, has been 

 appointed lecturer in physics in the South 

 African College, Cape Town. 



Dr. Alexander Tornquist, of Konigsberg, 

 has been invited to the chair of geology and 

 paleontology at Leipzig. 



Pkofessor His, of Berlin, who was asked to 

 accept the appointment of director of the med- 

 ical clinic, at Vienna, as successor of Pro- 

 fessor von Noorden, has declined. 



DISCUSSION AND COSBESPONDENCE 



A PECULLVR DERMAL ELEMENT IN CHIM.EROID 

 FISHES 



When recently in Washington, I was kindly 

 allowed by Dr. Hugh M. Smith to examine the 

 type of Chimcera deani Smith and Eadeliffe 

 (Philippine Islands), to see if I could discover 

 any scale-like dermal structures hitherto un- 

 reported. Gently scraping the side of the ani- 

 mal, I readily procured a number of small 

 scale-like objects, which when mounted and 

 examined with a microscope were seen to be 

 strongly curved rods, taking very nearly the 

 form of a horseshoe, >or of oval rings with the 

 lower end cut off. They measured about 640 

 microns in one direction and 500 across, with 

 the free ends somewhat tapering. Frequently 

 several were attached together in a series, the 

 top of each about 130 microns above the top 

 of the one following. Being much interested 

 in these peculiar structures, I asked Dr. Smith 

 to send me material of other chimseroids, and 

 this he very kindly did. In a young Hydro- 

 lagus colliei (Bennett), 5 inches long, I found 

 the structures in situ. A mucus canal about 

 2,180 microns below the dorsal denticles 

 was lined with these horseshoe-like structures, 

 placed obliquely a short distance apart, so that 

 each one partly overlapped two others, as seen 

 from above. The free ends project along the 



margins of the cajial, which is widely open 

 above, and the structures obviously serve to 

 keep the canal in shape and open. 



In the works of Garman, Dean, Bridge. 

 Jordan, etc., I find no mention of these stmc- 

 tures; but they may have been recorded in 

 some work not accessible to me in Colorado. 



T. D. A. COCKERELL 



Univeksity or Colorado 



LABELING MICROSCOPIC SLIDES 



To THE Editor of Science : I was interested 

 in the note published in Science, by Zea 

 Northrup, in the July 25 issue, on "A New 

 Method for Labeling Microscopic Slides," for 

 I have been following that method for the 

 last five years. I have found it a very suc- 

 cessful way in which to obtain a permanent, 

 clear designation for the slides. It is espe- 

 cially valuable in labeling serial sections, for, 

 as soon as the ribbon has been firmly attached 

 to the slides, the glass near the end of the 

 ribbon is easily cleaned and the label then 

 passes through the remaining parts of the 

 process, until finally it is covered with rhe 

 balsam and cover glass. This gives complete 

 permanency to the writing and only the de- 

 struction of the slide will result in the loss of 

 the label. In this connection it may be inter- 

 esting to some to speak of two features of 

 numbering slides which, though probably not 

 used exclusively by the writer, he has never 

 seen adopted by other workers. In numbering 

 a long series of slides which contain consecu- 

 tive sections from one imbedded object it is 

 convenient to assign a decimal number to the 

 individual slides. The practise of the writer 

 has been to assign a whole number to the en- 

 tire embedding of a certain object preceded by 

 the last two figures of the year number; thus 

 if a certain flower bud is the second piece of 

 imbedding which I have done this year the 

 number of that flower bud is 132. Then the 

 first slide cut from that imbedding is 132.1, 

 or the fifteenth slide is 132.15. It may also 

 occur that more than one piece of an object is 

 included under the serial number 132, in 

 which case the slide number for the fifteenth 



