1899] BIRDS AND THEIR SURROUNDINGS 3 



which shows in a striking manner the value of coloration harmonis- 

 ing with the surroundings. This model consists of a box lined with 

 light gray felt, but open at the top and front. In the middle of the 

 box are two rough figures of birds, each identical in size, and sitting 

 upon a perch. One is covered with the same gray felt as lines the 

 box, and the other is darker in shade above than the felt and lighter 

 than the felt below. A spectator standing close to the box sees both 

 birds clearly, but three or four feet away the darker bird is almost 

 invisible, and at six or eight feet entirely disappears from sight. The 

 reason for this is that the lighter under-colour of the darker bird 

 counteracts the shadow thrown by the top light, and makes the bird 

 appear an uniform colour at a little distance, while in the case of the 

 bird of the same colour as the surroundings a shadow throws it into 

 strong relief. This exhibit, which strikingly demonstrates colour 

 values, will be found in the small gallery leading from the central 

 hall to the British birds. 



The Skin and Fins of Ichthyosaurus. 



Dr. Eberhard Fraas, to whom we are indebted for our first informa- 

 tion concerning the outward form of the body in the extinct marine 

 reptile Ichthyosaurus, has just published a description of another 

 specimen from the Upper Lias of Wurtemberg, now in the National 

 Museum at Buda Pesth (Foldtani Kbzlbny, 1898, vol. xxviii. pp. 169- 

 173, pi. ii.). It is now absolutely certain that this dolphin-shaped 

 reptile had a small triangular fin on its back, and that the vertebral 

 column turned downwards into the lower lobe of the laterally-com- 

 pressed forked tail. It seems probable, however, that the newt-like 

 crest of skin supposed to extend along the back behind the dorsal fin, 

 was a deceptive appearance in the first specimen described. Four 

 examples of Ichthyosaurus, showing the outline of the body, are now 

 known from the Upper Lias of Wurtemberg — the first in the Stutt- 

 gart Museum, the second in a private collection at Brussels, the third 

 at Buda Pesth, and the fourth probably destined for the Museum of 

 the University of Tubingen. There is also a well-preserved detached 

 tail from the Bavarian Lithographic Stone in the Palaeontological 

 Museum, Munich. Thus rapidly, has our knowledge of the subject 

 progressed since Dr. Fraas first communicated his original drawing of 

 the Stuttgart specimen to Natural Science in September 1892 (vol. i. 

 p. 515). 



Books and the Customs. 



Jn a note on the dates of publication of Temminck and Laugier's 

 "Planches coloriees," that wonderful collection of illustrations of birds 

 first issued by Buffon, which has just appeared in the Ibis, Mr. Davies 

 Sherborn calls attention to a publisher's notice of much interest. 



