16 NATURAL SCIENCE. Jan., 1895. 



" We have frequently complained in these columns of the ex- 

 clusive conduct of scientific enterprises by persons not acquainted 

 with the sciences and not engaged in their pursuit. We will not 

 enumerate the blunders committed by such persons under such circum- 

 stances, as they have recently come under our observation ; but only 

 refer now to a question of taste in which some of these well meaning 

 persons have immortalised themselves in stone. A new building 

 for the use of the collections of the Academy of Natural Sciences 

 of Philadelphia was recently erected, chiefly from money appro- 

 priated by the Legislature of Pennsylvania. An entrance doorway 

 was devised, and in order that it should represent the uses of the 

 building, it was adorned with figures and reliefs of animals. Persons 

 possessed of the least spark of originality would have seen the propriety 

 of representing in these figures something appropriate to the country, 

 and if possible the institution. Nothing would have been easier than 

 to have placed at the entrance of the Museum, figures of some of the 

 forms of life discovered by its members. The idea was suggested to 

 the gentlemen in charge of the construction, but to commemorate in 

 so conspicuous a manner the services of the naturalists of the Academy 

 it did not strike them favourably. So it came that the apex of the 

 entrance was surmounted by, not even an African lion, but an official 

 British lion, with his mane brushed into a collar like Punch's dog, 

 such as one sees on Government buildings in Great Britain. On 

 each side is a lioness similar to those seen on buildings all over the 

 world. At the summit of one lateral column is a head of a hound, 

 and on the other side a ram with very unsymmetrical horns, both 

 foreign importations. Of the animals in relief above the door, the 

 only American animal is a crab, Lupa diacantha, which is indeed, very 

 appropriate to the building commission, as it generally goes back- 

 wards, and pinches its nearest neighbours." 



The Folds in the Gastropod Shell. 



Dr. Dall appears to have been on an exploring expedition 

 through one of his own papers, and to have realised that an idea of 

 great value contained therein was likely to receive less attention than 

 it deserved, because its environment afforded it too great facilities for 

 concealment. At any rate his theory as to "the mechanical cause of folds 

 in the aperture of the shell of Gastropoda " has been reprinted with 

 adaptations from the " Transactions of the Wagner Free Institute of 

 Science" (vol. iii., 1891), and now appears in the American Naturalist 

 for November. The theory is that the folds, or ridges, on the 

 columella, or central pillar, of many spiral gastropod shells, owe their 

 origin to the circumstance that the mantle of the animal, as it con- 

 tracts and withdraws into its house, is thrown into longitudinal folds, 

 and the shelly matter secreted by the mantle naturally collecting in 

 the furrows between these folds gets deposited in the lines of their 

 passage over the columella, thus layer by layer building up the shelly 

 ridges. The idea is so simple, yet apparently so satisfactory, that its 

 republication in an accessible form will, we hope, lead to its discussion 

 by competent observers, with a view to its proper testing by further 

 researches, and its establishment or rejection as a working hypothesis. 



