1883.] On the Skeleton of the Marsipohranch Fishes. 439 



From the second series — 



1 B.A. unit='98669xl0 9 C.G.S. 

 From the third series— 



1 B.A. unit=-98683x 10 9 C.G.S. 

 As a mean we take — 



1 B A. unit=-986i , 7 x 10 9 C.G.S. 



"With use of the ratio between the mercury unit and the B.A. unit, 

 found by us (" Proc. Roy. Soc." May, 1882) this gives — 



1 mercury unit= '94150 x 10 9 C.G.S., 



or, which is the same thing, the ohm is the resistance of a column of 

 mercury at 0° Cent., whose section is one square millimetre, and 

 whose length is — 



1062-14 millimetres. 



The very close accordance between the result of the present inves- 

 tigation, and that obtained by the method of the revolving coil ("98651), 

 and by Glazebrook ("98665), using another method again, leads us to 

 hope that no error of importance can have escaped detection. 



The Appendix is devoted to a record of experiments having for 

 object the determination of the absolute pitch of a certain tuning- 

 fork, which has served as the standard of time throughout all our 

 work upon this subject. It is believed that the method employed is 

 worthy of attention, and may be useful to other physicists. 



II. "On the Skeleton of the Marsipohranch Fishes. Part J. 

 The Myxinoids. (Myxine and Bdellostoma.) By W. K. 

 Parker, F.R.S. Received December 14, 1882. 



(Abstract.) 



At present nothing is known of the development of these remarkable 

 fishes, but their structure in the adult state is of great interest, and 

 as the other related type — the Lamprey — has had great attention 

 given to it lately, in most of its stages, I have thought it would be 

 profitable to anatomists to have a detailed account of the skeleton 

 in these lower and less known types. I received several specimens 

 of the adult Hag-fish (Myxine) from my friends the late Professor 

 Rolleston, F.R.S., and Mr. Frank Buckland ; for fine specimens of 

 the gigantic type {Bdellostoma) I am indebted to Professor Ray 

 Lankester, F.R.S. 



My guide in this work has been the excellent and most accurate 

 Johannes Miiller — his four memoirs (well known to anatomists) on 



2 g 2 



