Appellants seek review of the denial of their motion to reduce sentence under Fed. R.Crim.P. 35. As recorded in the docket entry, the court denied the motion December 1, 1976. Appellants filed a notice of appeal December 15, 1976. Under Fed.R. App.P. 4(b), the appeal was untimely.

A rule 35 motion is a proceeding in the original criminal prosecution. See Heflin v. United States, 358 U.S. 415, 418 n.7, 79 S.Ct. 451, 3 L.Ed.2d 407 (1959). Accordingly, the 10 day limitation of Fed.R. App.P. 4(b) governs. Appellants’ counsel may be charged with knowledge of the difference between a rule 35 motion and a petition under 28 U.S.C. § 2255.

*1218 We remand the ease to allow the district court to determine whether excusable neglect entitles appellants to an extension of the time for appeal.

REMANDED.