92 MR. S. S. UUCKMAX OX [vol. Ixxvi, 



even if they have heen figured in scientific literature, and found 

 their way to a museum. The type of Ammonites bucMandi is 

 said to have been discarded from its museum, relegated to a 

 rockery, and lost. It can hardly be this type which Buckland 

 carried like a French horn (as described by Sowerby), 1 because for 

 such a purpose inner whorls to at least a diameter of a foot must 

 be missing, and the type, if 2 feet in diameter, shows no more 

 than 6 inches diameter of lost whorls. Presumably, then, another 

 historic specimen of the Buckland collection has shared the same 

 fate. 



In between those four principal dates of such megalomorphs are 

 times when micromorphs held sway, the variations in size following 

 each other in a wave-like manner. 2 But this opens up a subject of 

 wide interest that may lead us away from the purpose of this 

 paper. Sufficient has been said to show, it is hoped, the advantage 

 and applicability of these technical terms : it is time to return to 

 the subject in hand. 



The questions to be -asked concerning the Hierlatz and Spezia 

 faunas are — how many specimens are colomorphs, and how many 

 species are micromorphs ? For, if certain specimens are colomorphs 

 of species which are really nomomorphs, their small size may be 

 said to be something of a natural accident, and no argument for a 

 small fauna can be based on them. Some specimens certainly are 

 colomorphs. Then there are other small specimens identified with 

 species which are fairly large (nomomorphs) in other localities — 

 are they also colomorphs, or are they really micromorphs, and, if 

 the latter, are they brephomorphs or phaulomorphs ? 



Considering how unreliable is the identification of Liassic 

 nomomorphs in, sa} r . the family Arietidse, and how little is known 

 about the inner whorls — the juvenile stages — of species supposed 

 to be familiar, one may perhaps be forgiven for expressing con- 

 siderable doubt about any identifications of small forms with 

 species only known by fairly large examples. But, supposing these 

 questions satisfactorily disposed of, and that there still remains a 

 micromorph fauna — anamorphs like Gymbites and catamorphs 

 like species of the two later waves of Schlotheimia, then, before 

 deciding that this micromorph fauna is special to particular areas, 

 it is necessary to enquire precisely as to the dates which it represents 

 and to see whether at such dates micromorph faunas existed 

 elsewhere. 



The phenomenon of small forms was, at certain dates, of 

 European extension : Hierlatz shares it with Gloucestershire ; in 

 fact, Gloucestershire would show a larger series of small forms 

 than Hierlatz, for the deposits which happen to have been preserved 

 there are those of the times when ammonites were mainly small, 

 and the deposits have a longer range in time than those of Hierlatz. 

 From Mercian 7 to Wessexian 1, a period of, say, possibly some 

 21 hemerse, about half were dates when ammonites did not exceed 



1 ' Mineral Conchology ' vol. ii (1816) p. 69. 



2 See, for partial illustration, Table X, p. 95. 



