Iv 



only just been published by Prof. Marsh, of Yale College, and 

 which differs from all known birds in having the centre of its 

 vertebrae doubly concave (a character hitherto found only in some 

 of the groups of reptiles), might be considered by one class of 

 students as a link between birds and reptiles, and by the other as 

 a reptile, such as Platydactylus homalocephalus, with its many- 

 lobed tai^, which had changed its scales to feathers. This bird 

 is about the size of a pigeon, and is to be named Ichthyornis 

 dispar. 



It is true indeed that the very indistinct and fragmentary con- 

 dition of many fossil insects prevents our studying them with 

 sufficient precision, but the student need only to cast his eyes 

 over the pages of Mr. Packard's most excellent ' Guide to the 

 Study of Insects' to see how greatly the fossil forms assist in the 

 general classification of those Articulata which form the subject 

 of his book. It is, however, amongst the Crustacea that we 

 naturally find far more numerous and more important materials 

 for this purpose, and we can well refer with national pride to the 

 noble memoirs on the fossil Decapoda Brachyura by Professor 

 Bell, on the Trilobites by J. W. Salter, on the Fossil Ento- 

 mostraca and Estherea by T. Bupert Jones, and on the Fossil 

 Cirripedes by C. Darwin, all published in the volumes of the 

 Palseontographical Society's ' Transactions.' A still more remark- 

 able series of papers is now, however, in course of publication by 

 the same Society, b}^ H. Woodward, on the Fossil Merosto- 

 mata, animals the great majority of which have onl}'^ recentl}'^ been 

 discovered, and which surprise us, not only from their strange 

 forms and interesting relations, but also from their including the 

 most gigantic of known articulated animals, some of them acquiring 

 a length of four feet, with a breadth of fifteen inches (Pterygotus 

 anglicus), whence they have been formed by Prof. Hackel into 

 a sub-order of Poecilopoda named Gigantostraca in his ' Generelle 

 Morphologie.' These creatures appear to be most nearly allied 

 to the order Xiphosura, or King Crabs (LimuHdse), on the one 

 hand, and to the Trilobites on the other. I regret that space will 

 not permit me to bring before you an analysis of the four parts of 

 Mr. Woodward's admirable ' Monograph of the British Fossil 

 Crustacea of the order Merostomata,' and that I must be content 

 to refer you to his other papers in the 'Geological Magazine' 

 (vols. viii. and ix.), and the ' Quarterly Journal of the Geological 



