nOO Mn. n. II. wiiiTEiiorsK ox the [Apr. 5, 



Till' following papt'i-s wltc road : — 



]. The Caudal Fin of tho TisLKOSTOMI. 



By liicnAUi) 11. AVihtkiiousk, M.Sc, 



University of ]>irniingliani.* 



[Ueceived Foliruavy 4, 1910.] 



(Plates XL\ai.-L.t and Text-figure 57.) 



Contents. 



1. Introduction, p. o90. 



2. Tenninolop:}', p. 592. 



3. Morplioloii'y, ]). 593. 



4. Gt-neral Conclusions, p. 620. 



5. Additioinil Note, p. 023. 



1. IXTRODUCTION. 



Wliile the study of the paired fins of iSshes, and also the dorsal 

 and anal among the median unpaired fins, has been pro.secvited in 

 great detail, a systematic, detailed investigation of the caudal iiu 

 seems to have received much less attention. Some authors have 

 dealt somewhat extensively with the subject, yet these have only 

 treated of a comparatively few species; it was thought advisable, 

 therefore, tliat such an important oi-gan as the caudal lin of fishes 

 should receive a broad treatment, and to carry out this pur})ose, 

 several scores of different species have been subjected to a detailed 

 examination of the skeletal parts of the fin. Tlie numbei' treated 

 of includes species from as many widely different families as it 

 has been possible to obtain, so that almost every form of tail 

 likely to occur should be made known. It is impossible to include 

 every type examined in the present paper, but the subject will be 

 completed at as early a date as possible. 



Tlie Teleostei will receive the fullest treatment, but some 

 reference will be made to other groups for the .sake of presenting 

 a more complete account of the piscine tail-fin. It has been 

 impossible, as yet, to investigate the tail of the ])i})noi. but it is 

 hoped that this grouj) also will be dealt with in due courst". 



IMatcrial for the work has been ol)tained fi'om various .sources, 

 th<' largest (luantity having been obtained at Naples during my 

 occupation of the IJritish A.ssociation table at the Zoological 

 Station in that town, during the six nu)nths endeil IMny, 1908. 

 Other valuable n)aterial has been supplied to me by a nundier of 

 friends. I should like to mention here that the wliole investiga- 

 tion is due to the suggestion of the late Professor Bridge, F.R.S., 

 under who.se superintendence the work was cai-ried out; it was a 

 ])leasure an<l fortune to have so able a critic and kindly adviser as 

 my late revered teacher. T wish also to express my best thanks 

 to the British As.sociation for ap[)ointiug me to occupy their table 



• Connnuninilcd by l>r. P. Cualmkks Mitchell, JI..\.. F.K.S. 

 f l'\n {•\\t\:\\n\{'\in\ of the I'lati's sit ]>. (!25. 



