148 REPORT — 1S59. 



Mollusca, recorded in the Transactions of the British Association for 1844 and 1847, 

 but merely with the view of showing what caution is necessary in drawing conclusions 

 from some of the instances recorded there. 



It is stated that, in Pectinidae, " corrugated membranous structure with tnbular 

 structure is sufficient to distinguish a shell of this family from any neighbouring 

 family to which in general characters it might possess an affinity ;" allusion is also 

 made to traces of cellular structure on the outside, a thin layer having been observed 

 in Pecten nobilis ; it is conjectured that the rarity of such cellular layer may be 

 owing to abrasion during the active movements of the animals ; the examination of 

 very young specimens is also recommended. 



While preparing some specimens illustrative of shell-structure for class demon- 

 stration, I found that the Pecten vitreus (P. Groznlandicus of some authors), an 

 Arctic species, the shell of which is singularly transparent, is well-suited for such 

 purpose, and has some peculiarities which seem deserving of record. Both valves 

 have a thin layer of membranous structure inside ; the whole of the convex valve has 

 tubular tissue on the outside : the body of the flat valve, on the other hand, is di- 

 stinctly cellular, while the auricular portion is tubular. The convex valve, therefore, 

 has the characters assigned in the Report above quoted ; while the flat presents three 

 kinds of tissue, in different parts of it, — viz., membranous, tubular, and cellular. 

 Specimens of different ages were found presenting the characters above stated. It is 

 obvious, therefore, that erroneous conclusions would result from any partial exami- 

 nation of this species. 



I was further induced to examine young individuals of a native species, Pecten 

 maximus ; specimens half an inch or even an inch broad are transparent enough for 

 the purpose. Here it is the convex valve which is cellular on the outside, and not 

 the flat valve (as in Pecten vitreus) ; for it has on the outside an obscurely tubular 

 structure with numerous granules interspersed. Of Pecten similis, which is very 

 translucent, I had only a few separate valves at disposal : some of these I found to 

 be cellular, and others obscurely tubular on the outside. 



In the Report already quoted, an example is given, illustrative of the importance 

 of shell-structure in determining affinities. A fossil was described by Professor 

 Phillips as an Avicula, and by Messrs. Young and Bird as a Pecten ; the mixture of 

 external characters is such as would sanction its being placed in either genus. 

 From the absence of cellular or membranous structure, which characterizes Avicula, 

 and the presence of corrugated and tubular tissue, it was inferred that this fossil 

 ought to be placed in Pectinidae : the facts above recorded seem to require a revisal 

 of such decisive conclusion. 



• 



On the Varieties and Species of New Pheasants recently introduced into 

 England. By John Gould, Esq., F.R.S. fyc. 



After a sketch of the distribution of the family of Gallinaceous birds, the author 

 gave an account of the species of the genus Phasianus (Pheasants) which had been 

 introduced into England. All the species were from Asia. The oldest-known was 

 the P. Colchicus from Asia Minor ; the next was P. iorquatus from Shanghai, which 

 was introduced about one hundred years ago, and had recently been reintroduced ; 

 and the third was P. versicolor, from Japan. The crosses between these three species 

 produced remarkably fine, strong and heavy birds. The other true species exhibited 

 was P. Mongolicus, from Mongolia. Mr. Gould also placed on the table specimens 

 of P. Soemmeringi from Japan, and P. Reevesi from China, a bird remarkable for 

 having a tail 6 feet in length. 



Mr. Gould exhibited several species of Birds of Paradise, for which he was in- 

 debted to Mr. Wallace, who had recently procured numerous fine examples of several 

 members of this beautiful family, and had moreover discovered a splendid new bird 

 (perhaps allied to this group), which had been named, in honour of him, Semioptera 

 Wallacei. The species exhibited were, Paradisea apoda from Arm Island ; P. 

 Papuana and P. rubra, Diphyllodes magnifica, Paroiia aurea, and Cicinnurus regius 

 from New Guinea ; and the new Semioptera Wallacei from the island of Batchian. 



