THE AMERICAN MUSEUM JOURNAL 



black or dark brown in color, whereas many of the non-com- 

 mercial sponges have brilliant hues and other attractive features. 

 Sponges as a class have existed in nearly all ages of the earth's 

 geological history, and in many periods were extremely abun- 

 dant and varied in form. 



The Museum recently has come into possession of a remark- 

 able series of fossil sponges from the collection of Dr. Schrammen 

 of Hildesheim, Germany, all of which are from the Cretaceous or 

 Chalk formation of northern Germany and are mostly from, in or 

 near the little towns of Misburg, Oberg and Nettlingen. These 

 sponges all belong to the great subdivision of the class in which 

 the skeleton is composed of siliceous, or glassy, spines (called 

 "spicules") and rods. The specimens from Misburg are in a 

 light-colored clay, in which the form and even the surface feat- 

 ures are pi-eserved. Those from Oberg have been skeletonized; 

 and although they are extremely fragile, they show the structure 

 of the sponge almost as well as do the living organisms. The 

 specimens from Nettlingen are preserved as iron oxide (yellow 

 ocher), and show only the external form, without the microscopi- 

 cal structure. Some of the most striking forms in the Schram- 

 men collection have been placed on exhibition in one of the desk 

 cases in the Geological hall. 



DEPARTMENT OF VERTEBRATE PAL.-EONTOLOGY. 



^^HE halls of vertebrate palaeontology have been com- 

 01);] I pletely rearranged in connection with the removal 

 of the Dinosaurs and other reptiles to the new 

 hall in the southeast wing. The fossil mammals are 

 now arranged on the " alcove system," replacing 

 the " aisle system " which has been found to be confusing to the 

 public. In the new system, each alcove at the side of the hall is 

 devoted eitlier to a single family or to closely related groups of 

 mammals, so tliat the \-isitt>r can readily get his bearings and, 

 especially, appreciate the remarkable force of the evolutionary 

 succession. The alcoves as at present arranged are as follows: 



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