Infantry Marine Service?

I had come across the name of DeWitt C. Hotchkiss of the 112th New York Infantry who had served aboard the USS Monitor as a member of the Infantry Marine Service.  I had never heard of this group, the Infantry Marine Service.

He received a Medal of Honor at the Second Battle of Fort Fisher, Jan. 15, 1865.

I inquired of the Yahoo! Civil War Navy and Marine Forum.

Steve Hesson called it a "confused collection of data.  The Monitor carried no "Infantry" or "Marines."  It sank in 1863 and was not at Fort Fisher.

Mason Howse said there was a Mississippi Marine Brigade Infantry from 1863 to 1865.  Both the Union and Confederate River defense coordinated with the Army.  The Marine Infantry was probably like a provost duty with different regiments assigned at different times.  It also could be a coalition of Marines and Infantry set up to storm fortified positions.

Chuck Viet said there was definitely confusion with a core of truth.  Hotchkiss probably served aboard a monitor, as the entire class was called and not THE Monitor.  He also believes there were a small number of infantry regiments designated as Marine.

Good and Confusing?  --Old B-Runner