( 669 ) 



XXIV. — A Monograph on the general Morphology of the Myxinoid Fishes, based on 

 a study of Myxine. Part III. Further Observations on the Skeleton. By 

 Frank J. Cole, B.Sc. Oxon., Professor of Zoology, University College, Reading. 

 Communicated by Dr R. H. Traquair, F.R.S. (With one Plate.) 



(MS. received October 1, 1908. Read December 7, 1908. Issued separately February 18, 1909.) 



The first and second parts of this work (7, 8), on the skeleton and muscles respectively, 

 were published in the Transactions of the Society for 1905 and 1907. The third part 

 would naturally have related to the viscera, and this, in fact, is in active preparation, 

 but it is first necessary to amplify the description of the skeleton. Figs. 1 and 2 in 

 my first part were based on dissections, which were executed very carefully, and the 

 results checked by the examination of serial sections. It is, however, peculiarly 

 difficult, and especially so in Myxine, to preserve the natural relations of the parts, and 

 these drawings therefore exhibit the defects incidental to the method by which they 

 were prepared. I mean by this, not that they are inaccurate, but that the inter- 

 relationships of the parts could not be faithfully represented. Quite apart from this, 

 however, it became necessary to re-draw these figures. A great part of this work is 

 based on the investigation of serial sections, and especially on one large and complete 

 series, carried as far back as the liver, which I succeeded in preparing after many 

 failures. Anyone who has attempted to obtain a series of the head of a 25 cm. 

 Myxine in which no sections shall have been lost, and each one flat and unbroken, will 

 have realised that this has been no light task. All the section work centres round this 

 one series, and it is hence important, for the purposes of co-ordination, that it should 

 be possible to compare the charts of the vascular and nervous systems, which I am 

 preparing, with similar charts of the skeleton based on the same series of sections. 

 Therefore I plotted the two charts illustrating the present paper, and I think it will 

 be found that these are not only necessary to the understanding of the future sections 

 of the work, but are otherwise an essential feature of the whole. I also add some 

 further notes on the anatomy of the skeleton on points which have been elucidated 

 since the publication of Part I. 



The expenses of this research have been defrayed by a grant from the Government 

 Grant Committee of the Royal Society. 



Simultaneously with the issue of my first part, an elaborate and important 



description of the micro-anatomy of the Myxinoid skeleton was published by 



Schaffer (28). In this memoir he states that the yellow-brown colour which the 



hard cartilage assumes after it has been in spirit is only superficial, and is due to a 



post-mortem imbibition of colouring matter from the blood. I have so far not found 



this discoloration supervene in formalin - preserved material, although Ayers and 

 TRANS. ROY. SOC. EDIN., VOL. XLVI. PART III. (NO. 24). 98 



' 



