The pair were unused replacements in Friday's 82-8 demolition of Portugal, but are two of 11 changes made by the England coaches for the Anglo-Scottish clash.
Despite running in a hat-trick against the Portugese winger Josh Skelcey misses out on the starting 15, as does lock Josh Peters, although both have been named among the replacements.
A win will put England within 80 minutes of repeating last year's title triumph, but Scotland are coming into the game battle-hardened after pipping Wales by a point in the opening round.
Tuesday's game is being played in Grenoble, France, at 6pm UK time.
Meanwhile Rugby School scrum-half Ben Pointon has been selected on the bench for England Under-18 Clubs and Schools' game against Ireland this Saturday.
ENGLAND UNDER-18 TEAM TO PLAY SCOTLAND
FIRA/AER Championship Semi-Final
Grenoble
Tuesday, March 26th, 2013
Kick off 6:00pm UK time
15 Howard Packman (Northampton Saints & Moulton College)
14 Tom Howe (London Wasps & Shiplake College)
13 Nick Tompkins (Saracens & Oaklands College)
12 Rory Jennings (Bath Rugby & Bryanston School)
11 Tom Fowlie (London Irish & St Pauls Catholic College)
10 Josh Sharp (Saracens & Oaklands College)
9 Stuart Townsend (Exeter Chiefs & Ivybridge College)
1 Luke Chapman (Exeter Chiefs & Truro College)
2 Jack Walker (Leeds Carnegie & Prince Henry's Grammar)
3 Paul Hill (Leeds Carnegie & Prince Henry's Grammar)
4 Jordan Onojaife (Northampton Saints & Stowe School)
5 Charlie Ewels (Bath Rugby & Bryanston School)
6 Andrew Hughes (Sale Sharks & Hartpury College)
7 Andrew Boyce (Worcester Warriors & Kings Worcester)
8 James Chisholm (Harlequins & Brighton College)
Replacements
16 Sam James (Saracens & Bishops Stortford)
17 Lewis Boyce (Leeds Carnegie & Prince Henry's Grammar)
18 Neale Farthing (Leicester Tigers & Wyggeston & Queen Elizabeth College)
19 Josh Peters (Northampton Saints & Oundle School)
20 Matt Bolwell (Exeter Chiefs & Truro College)
21 James Mitchell (Sale Sharks & Lymm School)
22 Josh Skelcey (Northampton Saints & Moulton College)
23 Louis Clayton-Molloy (London Wasps & Harrow School)
