NOTES ON ECHINODERM MORPHOLOGY. 21 



by the following difficulty. Miiller^ originally proposed the 

 name basals for those plates beneath theradialsof Peutacrinus 

 *' die mit den Kelchradien alterniren." They actually do form 

 the base or lowest part of the calyx in the great majority of 

 Crinoids ; and it therefore seemed inexpedient to retain this 

 name only for plates which are radial in position and of less 

 frequent occurrence, although it had been erroneously applied 

 to them by Miiller, This would certainly have been a greater 

 change than the one which I proposed, though probably less 

 paradoxical to non-morphologists. But it would have inevitably 

 have led to the belief that a " Basis " is present in compara- 

 tively few Crinoids, instead of being universal as MUller 

 described it. 



There can be no true "Science of Ancient life" which is 

 not based upon the facts and deductions of morphology, subtle 

 as the latter may appear to be to the collector. For without 

 them palaeontology degenerates into the compilation of empi- 

 rical descriptions of fossils, accompanied by the details of their 

 geological positions ; and these, however important to the 

 geologist, are almost entirely devoid of any value to the 

 biologist. How could Cope, Marsh, Leidy, and other well-known 

 American palaeontologists, properly describe the marvellous new 

 generic types which they so often discover, without a rational 

 system of nomenclature based upon vertebrate morphology ? 

 Considerations such as these led me to the use of the terms 

 basals and under-basals for the two rings of plates between the 

 stem and the radials of dicyclic Crinoids ; and they have been 

 adopted, I am glad to say, by Wachsmuth and Springer, 

 Barris, Wetherby, H. S. Williams, de Loriol, and other writers 

 who are frequently describing new Crinoids. 



One point more is worth noticing. Loven, Wachsmuth, and 

 Springer, and Agassiz consider the under-basals as representing 

 the dorsocentral plate of the young Urchin. I have already 

 endeavoured to show that this position is untenable, and would 

 urge one more argument against it. Not only has Marsupites 



' " Ueber den Bau des Pentacriiius caput-Medusae," ' Abhaudl. d. Berlin 

 Akad.,' p. 25 (of separate copy). 



