136 PROCEEDINGS OF THE ACADEMY OF [March, 



addition, the Museum obtained a nearly complete skeleton of a 

 fossil porpoise belonging to the family Delphinidse. This specimen 

 comprises the skull and mandible, about thirty vertebrae, many pairs 

 of ribs, a scapula, limb-bones, and numerous teeth, including several 

 in situ. It is possible from this material to determine accurately 

 the characters of the species. The skull is distinctly delphinoid, 

 but the crowns of the posterior teeth, instead of being simple and 

 conical, as in typical recent Delphinidse, are trituberculate, with 

 rugose enamel. The cervical vertebrae are all separate, the neural 

 spines of the thoracic vertebrae erect, the transverse processes of the 

 lumbar vertebrae long and slender, but not acuminate, and the ulna 

 furnished with a lunate olecranon. 



The new species appears to belong to the genus Delphinodon, 

 which is based on two or three forms known only from detached 

 teeth, and hitherto regarded as belonging to the Squalodontidae. 

 From the evidence furnished by the new material, the genus should 

 probably be transferred to the Delphinidae. 



Henry H. Donaldson, Ph.D.: "The Historv and Zoological Position 

 of the Albino Rat."* 



There are two common rats in the United States: Mus rattus, 

 the black rat, together with Mus rattus alexandrinus — its gray 

 variety — and Mus norvegicus, the common brown or Norway rat. 

 Mus rattus entered Europe from the east about the thirteenth century 

 and spread widely, reaching America on the ships of the early ex- 

 plorers and colonists. Mus norvegicus, also coming from the East, 

 did not arrive in Europe until the beginning of the eighteenth cen- 

 tury and in America not until 1750 or 1775. Wherever the Norway 

 rat has gone it has displaced the Mus rattus. The common albino 

 which we see to-day is a strain of the Norway rat. It seems probable 

 that at one time albinos of Mus rattus must have existed, but they 

 are nowhere to be found at present. The origin and history of the 

 existing albinos is obscure, but there is no evidence that they have 

 established themselves in open competition with the pigmented forms. 



They are always found under conditions of domestication. This 

 manner of life has led to some structural modifications, and especially 

 noticeable is the diminution in the weight of the central nervous 

 system. 



Although all albinos breed true to color, yet their composition is 

 not identical, as is shown by the fact that in crosses of extracted 

 albinos with pigmented forms, the color markings of the progeny 

 are modified according to the ancestry of the albino. A pure strain 

 of albinos is therefore not obtainable. 



Edward B. Meigs, M.D., and L. A. Ryan, Ph.D.: "The Ash of 

 Smooth Muscle." 3 

 The smooth muscle of the bull-frog's stomach has been analyzed 

 quantitatively for potassium, sodium, iron, calcium, magnesium, 



3 The entire article in The Journal of Biological Chemistry, May, 1912. 



