Dr. J. E. Gray on North American Testudinata. 285 



with the animal ovum, where a similar coating is well known to 

 be produced over it^ exactly at a corresponding period. 



In a separate paper*, I have pointed out many singular ano- 

 malies observable in the structure of seeds, that are not reconcile- 

 able with the ordinary hypothesis. I have since collected nu- 

 merous other curious and novel facts tending to support my 

 views, showing the unusual developments observed in the Col- 

 letiecB and in the Rhamnacea in general, the still more novel 

 form of growth of the seeds of the AnacardiacecBj the peculiar 

 structure in those of the Styracea, Canellacea, Winteracece, 

 Lardizabalacece, and several other families, of which, after patient 

 research and careful investigation, I have prepared monographs, 

 which in succession will appear in this Journal, and which will 

 afterwards be reproduced in my 'Contributions' accompanied 

 by numerous plates and copious analytical details. In most 

 cases, in the above-mentioned families, the outer coating of the 

 seed appears under the form of a crustaceous shell, exterior to, 

 and quite free from a fleshy tunic, which encloses the cord of 

 the raphe within its tissues : although the former coating is 

 usually designated as the testa, it cannot under any hypothesis 

 be considered as a development of the primine : it appears to 

 me a perfect arillus, — satisfactory proof of which is offered in 

 Lardizabala, Lithrcea, and numerous other instances. 



XXVI. — Some Observations on Professor Agassi^ s Criticisms on 

 the " Catalogue of Shield Reptiles in the Collection of the 

 British Museum:' By Dr. J. E. Gray, F.R.S., V.P.Z.S., 

 P. Ent. Soc. &c. &c. 



I HAVE lately received, through the kindness of the author, a copy 

 of Professor Agassiz's "Contributions to the Natural History 

 of the United States : First Monograph, in Three Parts : I. Essay 

 on Classification. 11. North American Testudinata. III. Em- 

 bryology of the Turtle, with thirty-four Plates,^' a highly valu- 

 able and very important contribution to the natural history of 

 the Testudinata ; and which is accompanied with a large number 

 of remarkably well executed plates, showing the development of 

 the embryo and the young animal of several species of the Testu- 

 dinata inhabiting the United States, and some plates showing 

 the change in the general colours of one of the species. In the 

 Appendix and Errata to this work there occur, among observa- 

 tions respecting the ' Catalogue of Shield Reptiles,' the follow- 

 ing remarks : " Among his [Dr. Gray's] North American Emys 

 there are several which are only nominal species. I trust 



* Linn. Trans, xxii. 97. 



