Nikon has skipped the lens hood model HB-44 in their product line:
HB-47 AFS 50/1.4
HB-46 AFS 30/1.8
HB-45 AFS 18-55VR
HB-44 new lens ??
HB-43 45/2.8 PC-E
HB-42 60/2.8 micro
HB-41 24/3.5 PC-E
HB-40 AFS 24-70/2.8
HB-39 AFS 16-85
HB-38 AFS 105/2.8 VR micro
HB-37 AFS 55-200VR
Is the HB-44 reserved for a new, unreleased lens?
Via Nikoncafe