PROF. MARSH ON TYPE SPECIMENS. 1 59 



names to the category. A third investigator, with better opportu- 

 nities and more knowledge, may perhaps secure entire skulls or 

 even skeletons from the same horizon, and thus lay a sure foundation 

 for a knowledge of the fauna. 



As the number of described forms increases, the necessity of 

 a direct comparison of types becomes imperative, and the com- 

 parative value of each type specimen is thus brought into notice. 

 It will then frequently be found that not a few are uncharacteristic, 

 while others are too incomplete to disclose their own essential 

 features, and hence of little aid in indicating the affinities of forms 

 found with them. 



Type specimens that do not shew characteristic features are, of 

 course, of little value to science, and many such prove a delusion 

 and a snare to the investigator, however faithfully he ma}' endeavour 

 to study them. The imperfect types require still more labour to 

 decipher them. Not a few specimens to-day are types, for the 

 simple reason that they are imperfect. If they had been entire 

 when described, their true nature would have been recognized, and 

 much confusion in nomenclature have been avoided. The chance 

 preservation of some marked features may, indeed, give a hint as to 

 what the whole specimen once was, but too often a suggestion only 

 is thus offered, while the real nature of such types must always 

 remain in doubt. 



A type in Paleontology should consist of the remains of a 

 single individual, and this should stand as the original representa- 

 tive of the name given. A second specimen, or even more, may 

 be used later to supplement the first, but not to supplant it. This 

 substitution, however, has been made by some authors, with the 

 natural result of causing endless confusion in the nomenclature. 



TJie Selectmi of Type Specimens. 



The descriptions in Paleontology are too often descriptive only, 

 and not comparative. Such work, if well done, is preferable to 

 academic discussions in regard to the affinities of a specimen of 

 which the main characters are not known, or not placed on record. 

 A vertebra of a reptile, or the tooth of a mammal, if perfect and 

 characteristic, may form a type that will be distinctive enough for 

 the present requirements of the investigator. What the future 

 may demand, will depend upon the advance of knowledge in that 

 branch of science. 



In the choice of specimens worthy of being types, I can only 

 suggest a course that seems to me the proper one. I believe 

 experience has already shown that to make types of incomplete 

 or uncharacteristic specimens is seldom of permanent advantage to 

 an author, and almost always a lasting injury to the branch of 

 science he represents. There are more good specimens waiting to 

 be found than any naturalist can possibly describe, and one such 

 specimen is worth many of inferior grade. 



