_Polyommatus Venus._ Plate XXVII. Figs. 1 and 2. 193 _Polyommatus Achæus._ Plate XXVII. Figs 3 and 4. 194 GENUS THALIURA 195 _Thaliura Rhipheus._ Plate XXVIII. 197 GENUS URANIA 200 _Urania Sloanus._ Plate XXIX. Fig. 1. 202 _Urania Leilus._ Plate XXIX. Fig. 2. 203 _Rhipheus Dasycephalus._ Plate XXX. 205 Portrait of Lamarck 2 Vignette, Title Page 3 In all, Thirty-two Plates in this Volume. With one Plate double, making the number equal to THIRTY-THREE. MEMOIR OF LAMARCK. MEMOIR OF LAMARCK. Among the many eminent French naturalists, whose loss to science we have so often had occasion to lament during the few past years, the above individual occupied a conspicuous place. He was long known in Paris by his public prelections, and his numerous writings have procured for him a high degree of reputation throughout Europe. In this country he is best known by his admirable works on invertebrate animals, which may be said to have formed a new era in the history of that extensive department of the animal kingdom. But his studies had a very extensive range; many of the most interesting inquiries which for ages have fixed the attention of mankind, were the subjects of his meditation, and on most of them he formed a number of definite ideas which he promulgated under the form of theories. Although these speculations are of a highly fanciful description, and some of them greatly to be deprecated on account of their hurtful tendency, yet they merit attention as the productions of a mind remarkable for originality and penetration, as well as for extensive and varied knowledge. * * * * *