I just discovered the arrival records for the Morris Efron of St. Louis family. Mother Chaje (Ida SURASKY Efron) arrived with her three children, Yankel (Jacob), Mordic(?) (Max) and Gerson (Harry) under the family name EFRAIM. The ship record can be found at http://www.ellisisland.org/ by entering a search for Chaje Efraim arrival in 1900. They sailed from Glasgow, and indicated their last place of residence was Rotterdam. Perhaps Harry was born in either Rotterdam, before they could board their ship, or in Glasgow -- or on the way to Glasgow. Oral history says that Harry was born en route to the U.S., but this ship manifest says he is two-years-old.
I also found the arrival for Morris, under the name of Moische EFROM, also in 1900. On his arrival record, sailing from Rotterdam, it says .he is going to join his cousin, "S. KAPLAN," of Essex St. in NYC. A search of Kaplans with origins in Knyshin located an arrival for a Sore Kaplan from Knyshin (or some spelling variation thereof). This Sore is going to her husband James and brings with her a son and daughter. The family was found in the 1900 and 1910 census. In the 1910 census, the family has living with them two single women in the early 20s, Rebecca and Sarah Surasky. Those two boarders verify that it is the correct Kaplan family! In 1910, the Kaplan family is comprised of James, Sallie (Sarah), Jennie (Dwore?), Hyman (Chaim) and Mamie.
My search and discovery of this new information was motivated by the naturalization papers of Harry Efron, which papers were newly available on Ancestry.com .