PHILOSOPHICAL SOCIETY OP WASHINGTON. 193 



were 53° and "73° respectively; a temperature 1° to 14° lower 

 than on the Asiatic side. 



He also pointed out the courses of the Equatorial and Asiatic 

 ■currents of the Pacific Ocean, and the indications of a current of 

 cooler water flowing southward along the western coast of North 

 America. «» 



Mr. Dall made remarks on currents and temperatures in the 

 Sea of Oskotch and Behring's Bay and Straits, calling attention 

 i;o the shoalness of the latter. 



142d Meeting. April 2Y, 1878. 



Vice-President Taylor in the Chair. 

 Twenty members and visitors present. 

 Mr. Edgar Frisby made a communication on 



SERIES. 



Remarks on the subject were made by Mr. E. B. Elliott. 

 Mr. W. H. Dall addressed the Society on 



THE RESULTS OF RECENT INVESTIGATIONS INTO THE NATURAL 

 HISTORY OF THE CHITONID^, 



made independently by Dr. H. von Jhering of Erlangen and him- 

 self. He summed up the results of each investigator as follows : — 

 Dr. Von Jhering finds the sexes of all species examined by him 

 separate; the eggs are impregnated within the body of the parent ; 

 in the species he examined tlie eggs in the ovary are inclosed in 

 a sort of follicle which in Chiton squemosus secretes a membrane 

 like a chorion which is provided with radiating thornlike pro- 

 cesses. He .detects the presence of a dendritic renal organ in 

 the perivisceral cavity, which is lined with a ciliated membrane 

 and opens by a duct in the median line below the ai)us ; the mus- 

 cular fibres are bunches of fibrillse invested by a follicular sarco- 

 lemma, and those of the pharynx, in his opinion, are not striated 

 in the sense in which those of vertebrates are said to be striated. 



