The American Natu 



[April. 



Cephalopod arms ha< hren certainly shown.' " Prof. Grobben at the 

 same meeting replied saying, among <»thei things, that the radula and 

 pleural ganglia had no diagnostic value, since there was some evidence 

 that the ancestors of the Lamellibranchs had a radula which had 

 secondarily been lost, while the existence of the pleural ganglia in the 

 Nuculida?, the oldest of existing niolhws. had great weight. He had 

 no ground to alter his previous view that the Dentalidse were the 

 modified descendants of the group from which the Cephalopods had 

 sprung. The arguments advanced by Plate for regarding the arms of 

 the cuttle fishes as pedal were not conclusive. Profs. Biitschli and 

 Leuckart spoke to a similar effect, the latter assigning these forms a 

 middle position between Gasteropods and Lamellibranchs. 



The Genera of Enteropneusta.— Prof. Spengel 1 recognizes 

 among the 19 known species of this group four genera, separated most 

 sharply by the body musculature. In Ptychodera alone is there an 

 outer circular musculature; Glandiceps and Schizocardium have 

 inner circular muscles, while in Balanoglossus proper no ring muscles 

 exist. Other differential characters are given. Cephalodiscus is not 

 recognized as a member of the group. No species are mentioned. 



Extinct or Nearly Extinct Vertebrates.— Mr. A. F. Lucas 

 has a readable article upon the animals which are recently extinct or 

 threatened with extinction as represented in the National Museum. 2 

 The West Indian Seal (Monachus tropicalis), is uncertainly placed in 

 this category for but little is known of it, and its habits and habitat 

 seem favorable for its perpetuation. The California sea-elephant 

 (Macrorhini -sibly entirely extinct, none having 



been recorded since 15 were sent in 1884 to the National Museum. 

 The walruses, too, are threatened with extinction, the Pacific species, 

 Odobeenus obesus, being in greater danger than the Atlantic 0. rosma- 

 rus. The source of danger lies in the whalers who capture the 

 animals for oil and ivory. Between 1870 and 1880 there was brought 

 to market 1,996,000 gallons of walrus oil, and 398,868 pounds of wal- 

 rus ivory. In 1879 the ivory was worth 45 cents a pound ; in 1880, 

 $1.00 to $1.25; and in 1883, $4.00 to $4.50. The European 



t present restricted to Lithuania 



and the 



Caucasus, is protected in both localities. In 1880 the Lithuania? 

 herds numberd but 600 and the number is "smaller at present. The 



Isch. i.47,1891. 



r 1888-89, p. 609, 1891. 



