220 FOURTH REPORT 1834. 



rect. This memoir, which was published in tiie Ann. des Sci. 

 Nat. *, is illustrated by coloured sections of the two animals, 

 and its author shows that there are still many organs present in 

 each not found in the other, and tliat many of those common to 

 both are not, as was supposed wovild be the case, in the same 

 relative situation. In short, he attempts to demonstrate that, 

 pushed beyond a certain point, the analogy utterly fails. Du- 

 ring last year (1833) a second memoir appears to have been read 

 byM. Meyraux on these animals f, in which he still retains his 

 former theory, and, moreover, expresses an opinion that the 

 Cephalopoda ought to constitute an intermediate class between 

 the 3Iollusca and the Vertehrata, their general organization de- 

 parting much from the type of the former division, at the same 

 time that it approaches that of the latter. This is in accordance 

 with the opinion formerly advanced by Mr. MacLeay, who in his 

 Hor. Entom. considered the Cephalopoda as constituting an 

 osculant group between the two large divisions just mentioned %• 

 Like Mr. MacLeay, M. Meyraux would seem also to consider 

 them as showing considerable affinity to the Chelonian Rep- 

 tiles. Perhaps, however, the final elucidation of this pohit must 

 wait for the discovery of some intermediate form, which it is 

 not too much to hope may yet occur at some future period. 



A few other memoirs require to be pointed out as valuable 

 contributions to our knowledge of this class, although not con- 

 nected with the subject particularly discussed in those just 

 alluded to. Foremost amongst these is a memoir by Mr. Owen 

 on the Pearly Nautilus, published in 1832 §. This very valu- 

 able treatise contains a detailed account of the anatomy of the 

 animal inhabitant of the above shell, so often sought for since 

 the time of Rumphius, its original but imperfect describer. The 

 specimen dissected, which is the only one that has been 

 discovered in modern times ||, notwithstanding the frequent 

 occurrence of the shell itself, was taken by Mr. George Bennett 

 off the New Hebrides in 1829. Mr. Owen has shown that its 

 organization, although exhibiting some differences, more par- 



* torn. xix. p. 241. 



t See L'Instttut, No. 21, p. 180. lonlyknow the memoir from the analysis 

 which is there given of it. 



X Meckel is also stated to have proposed the making a distinct division of 

 the Cephalopoda, intermediate to the Vertehrata and Invertehrata. I am un- 

 able, however, to refer to the work in which he has advanced this proposal. 



§ Memoir on the Pearly Nautilus (Nautilus Pompilius, Linn.), with illustra- 

 tions of its external form and internal structure. Lond. 1832, 4to. 



II A fragment of a Cephalopod animal, supposed to belong to the Nautilus 

 Pompilius, was brought from the Moluccas by MM. Quoy and Gaimard, and 

 described in the Ann. dcs Sci. Nat. (torn. x.'i. p. 470.), but there are great 

 doubts as to its identity with that species. 



