The potential debutants are Edinburgh trio Blair Kinghorn (full-back), scrum-half Nathan Fowles and prop Murray McCallum, plus Glasgow Warriors prop D’arcy Rae.

John Barclay continues as captain as Greig Laidlaw returns to the squad after recovering from an ankle injury.

Worcester back-rower David Denton returns to the squad, as does Edinburgh centre Mark Bennett, who has recently returned after a long-term knee injury.

Gregor Townsend hailed the uncapped Blair Kinghorn's performances for Edinburgh. Picture: SNS Group

There is no place for hooker Fraser Brown, who has suffered a number of head injuries this season, but there is a return for Scott Lawson of Newcastle Falcons.

Townsend said: “With the announcement of this 40-man squad, we are now entering the key stages of our preparation for this year’s NatWest Six Nations Championship.

“It’s a bigger squad than we originally planned – which is largely down to the competition for places – with a number of players having performed well in the Autumn Tests and a few others putting their hands up for selection in recent weeks.

“We welcome Blair Kinghorn into our group for the first time, who has been in excellent form with Edinburgh this season, and also three of our most experienced players in Richie Gray, Greig Laidlaw and Scott Lawson.

D'arcy Rae is the only uncapped Glasgow Warriors player in the squad. Picture: SNS Group

“We are looking forward to working with them and the rest of the squad to ensure that we build on the momentum the players generated in 2017.”

In addition to the squad, three players have been invited to train with the group: Luke Crosbie (Edinburgh), Darcy Graham (Edinburgh) and Adam Hastings (Glasgow Warriors).

The squad comprises 17 Glasgow Warriors players, 11 from Edinburgh, three from Newcastle Falcons including Jon Welsh, two from Saracens, and one each from ASM Clermont Auvergne, Scarlets, London Irish, Leicester Tigers, Worcester Warriors, Sale Sharks and Toulouse.

SCOTLAND SQUAD FOR 2018 NATWEST 6 NATIONS

BACKS (19)

Mark Bennett (Edinburgh Rugby) – 20 caps

Alex Dunbar (Glasgow Warriors) – 28 caps

Nick Grigg (Glasgow Warriors) – 1 cap

Chris Harris (Newcastle Falcons) – 1 cap

Stuart Hogg (Glasgow Warriors) – 55 caps

Pete Horne (Glasgow Warriors) – 28 caps

Ruaridh Jackson (Glasgow Warriors) – 32 caps

Huw Jones (Glasgow Warriors) – 11 caps

Lee Jones (Glasgow Warriors) – 7 caps

Blair Kinghorn (Edinburgh Rugby) – uncapped

Greig Laidlaw (ASM Clermont Auvergne) – 58 caps

Sean Maitland (Saracens) – 29 caps

Byron McGuigan (Sale Sharks) – 2 caps

Ali Price (Glasgow Warriors) – 11 caps

Henry Pyrgos (Glasgow Warriors) – 27 caps

Finn Russell (Glasgow Warriors) – 32 caps

Tommy Seymour (Glasgow Warriors) – 39 caps

Duncan Taylor (Saracens) – 21 caps

Nathan Fowles (Edinburgh Rugby) – uncapped

FORWARDS (21)

John Barclay CAPTAIN (Scarlets) – 66 caps

Simon Berghan (Edinburgh Rugby) – 5 caps

Jamie Bhatti (Glasgow Warriors) – 3 caps

Magnus Bradbury (Edinburgh Rugby) – 2 caps

David Denton (Worcester Warriors) – 35 caps

Cornell Du Preez (Edinburgh Rugby) – 5 caps

Grant Gilchrist (Edinburgh Rugby) – 18 caps

Jonny Gray (Glasgow Warriors) – 38 caps

Richie Gray (Toulouse) – 64 caps

Luke Hamilton (Leicester Tigers) – 1 cap

Rob Harley (Glasgow Warriors) – 20 caps

Scott Lawson (Newcastle Falcons) – 46 caps

Murray McCallum (Edinburgh Rugby) – uncapped

Stuart McInally (Edinburgh Rugby) – 12 caps

Gordon Reid (London Irish) – 27 caps

D’arcy Rae (Glasgow Warriors) – uncapped

Ben Toolis (Edinburgh Rugby) – 7 caps

George Turner (Glasgow Warriors) – 2 caps

Hamish Watson (Edinburgh Rugby) – 15 caps

Jon Welsh (Newcastle Falcons) – 11 caps

Ryan Wilson (Glasgow Warriors) – 32 caps

Six Nations: Uncapped quartet named in Scotland squad