Cole, Bibliography of the Ichthyopsida. 215 



As, of course, the lateral line system may be traced in 

 many fossil fishes, the literature of which I was largely unac- 

 quainted with, I sought the co-operation of Dr. Ramsay Tra- 

 quair, F. R. S. , to whose accurate and laborious researches 

 fossil ichthyology owes so much, and who kindly referred me to 

 all the relevant publications, and drew up a list of all the types 

 in which the system had been described and figured. 



Besides the difficulty of the fossil literature, another 

 stumbling block, which must inevitably in some instances, but 

 I hope not in many, prove fatal, is that it frequently happens 

 that an author's text not only goes beyond his title (which pre- 

 sumably often cannot be helped), but that the title itself may 

 be absolutely misleading. For example, who would suppose 

 that a work entitled, " De musculis et glandulis observationum 

 specimen " contained a description of the cranial nerves of the 

 skate ? It is obviously impossible to make the bibliography 

 complete in this respect, where contemporary authors with un- 

 equivocal titles have not referred to them in their texts or lists 

 of literature. Again, Prof. Max Fijrbringer has recently pub- 

 lished a work entitled. " Ueber die spino-occipitalen Nerven 

 der Selachier und Holocephalen und ihre vergleichende Mor- 

 phologic." The original observations in that magnificent woik 

 extend considerably beyond : (i) the spino-occipital nerves, and 

 (2) the Selachia and Holocephala. The result of such action 

 as these two authors have exemplified is that the bibliographer 

 has practically to read through every work he consults, and to 

 consult twice as many works as he records. 



With regard to the question of dates, it often happens 

 that as many as three or even four dates may be given to one 

 paper. For instance, there may be the official year of a Socie- 

 ty (which often indicates the volume instead of consecutive 

 numbers), the date of the part in which the paper appears, the 

 date on which the paper itself is published, and the date at the 

 foot of the title page of the volume. I have disregarded any 

 difference in date which does not run into a different year, but 

 have otherwise given all possible dates which may be quoted 

 for a paper. For example, if a paper is quoted as 1884 (Hft.) 



