Editor's note: Many readers have taken issue with the assertion that this is the first time that U.S. service members have not been paid due to an appropriations lapse. We did some historical digging of our own. While this is the 21st government shutdown since 1976, most have been very short, and others, such as the Clinton-era shutdown in 1995-1996 and the Obama-era shutdown in 2013, have been accompanied by legislation that protected military pay. However, there was a period in 1877 when the U.S. Army went unpaid after Congress adjourned without passing an appropriations bill. So we've added the word "recent" to the headline.

As Coast Guard paychecks went undelivered Tuesday as the result of an ongoing partial government shutdown, the service's top officer urged its members to stay the course.

In a public letter published Tuesday afternoon on his social media pages, Adm. Karl Schultz said the day's missed paycheck, to his knowledge, marked the first time in the history of the nation "that service members in a U.S. Armed Force have not been paid during a lapse in government appropriations."

The Coast Guard, the only military service to fall under the Department of Homeland Security, is also the only service with payroll affected by the shutdown, which began Dec. 22. The Coast Guard was able to issue final paychecks for the year, but will be unable to distribute further pay until a budget deal is reached or another appropriation agreement is made.

In all, some 55,000 Coast Guard active-duty, reserve and civilian members are going without pay; the number includes 42,000 active-duty service members.

Coast Guard civilians have been on furlough or working without pay since the shutdown began.

While some government employees affected by the shutdown have been furloughed, the Coast Guard continues to conduct operations around the world.

"Your senior leadership, including [DHS] Secretary [Kirstjen] Nielsen, remains fully engaged and we will maintain a steady flow of communications to keep you updated on developments," Schultz said in his letter. "I recognize the anxiety and uncertainty this situation places on you and your family, and we are working closely with service organizations on your behalf."

Schultz added that Coast Guard Mutual Assistance, the service's official military relief society, received a $15 million donation from USAA to support those in need. The American Red Cross will help distribute the funds, he said.

The Coast Guard Mutual Assistance Board is also offering increased interest-free loans to junior employees and junior enlisted service members.

"I am grateful for the outpouring of support across the country, particularly in local communities, for our men and women," Schultz said. "It is a direct reflection of the American public's sentiment towards their United States Coast Guard; they recognize the sacrifice that you and your family make in service to your country."

The Coast Guard, Schultz said, had already many times proven the ability to rise above adversity.

"Stay the course, stand the watch, and serve with pride," he wrote. "You are not, and will not, be forgotten."

-- Hope Hodge Seck can be reached at hope.seck@military.com. Follow her on Twitter at @HopeSeck.