On a snowy morning in February of 1979, the plaintiff suffered injuries when her automobile, while stopped at a traffic light at an intersection in Somerville, was struck in the rear by another vehicle. She did not see what hit her. After the impact she saw a bus stopped 50 to 200 feet across the intersection from her vehicle. She observed the bus to be colored grey, silver and white, and, based upon her experience, she identified it as a Massachusetts Bay Transportation Authority (MBTA) bus. The plaintiff noticed the number “6166” in large white print at the right corner of the bus’s rear window. She testified that she wrote down the number “6166” with a pencil and paper given to her by Harold West, the driver of a truck that had been traveling behind her. West had come to the plaintiff’s assistance. West’s testimony at trial was that he saw a bus leave a ramp leading from the McGrath highway, attempt to fit between the plaintiff’s car and an island in the road, and strike the plaintiff’s car. West also described the bus as an MBTA bus. He too saw the number “6166” on the rear window of the bus and wrote it down on a piece of paper. The plaintiff and West waited for a few minutes for the driver of the bus to come over to them. The driver did not disembark, however, and the bus quickly drove off.
The plaintiff brought a negligence action against the MBTA in the Superior Court on February 8, 1980. On September 8, 1987, the plaintiff filed a motion to amend her complaint to add Lo-Law Transit Management (Lo-Law) as a defendant. The motion was allowed on September 9, 1987. Lo-Law had received no notice of the motion and-was-not present at the hearing. Lo-Law first learned of the claim when it was served with a summons on September 15, 1987.
The case was tried before a jury in February of 1988. There was evidence that the MBTA had sold bus number *47 6166 to Lo-Law on January 9, 1978, and that on the date of the accident the bus was in Lo-Law’s control. It was regularly operated, however, only in the Lowell area. The jury answered special questions as follows: Lo-Law, not the MBTA, owned and controlled the bus at the relevant time; Lo-Law was causally negligent in its operation of the bus; and the plaintiff's damages were $45,000. Judgment entered accordingly, and Lo-Law appealed.
We agree with Lo-Law’s contention that the trial judge improperly made remarks during his instructions which had the effect of taking the negligence issue from the jury. We, therefore, order a new trial on the issue of Lo-Law’s negligence. We also agree that, although improper in form, Lo-Law’s attempt to raise the issue of the plaintiff’s allegedly prejudicial delay in bringing the claim against Lo-Law was worthy of consideration. On remand, therefore, that issue may be heard.
1. The negligence issue was not waived. Lo-Law denied in its answer that it was negligent, and negligence was never expressly conceded. The plaintiff, therefore, had the burden of proving Lo-Law’s negligence by a fair preponderance of the evidence. Although the principal issue at trial was ownership of the bus, there was testimony, both on direct and in cross-examination, from both the- plaintiff and West about the accident, the extent of their particular observations, and the road and weather conditions. As Lo-Law denied that one of its buses was involved in the accident and claimed that its buses only operated in the Lowell area, it is understandable that, apart from the occurrence of the accident, there was no direct evidence that Lo-Law’s operator was not negligent. Lo-Law’s closing argument focused on the ownership issue; negligence was not discussed. Lo-Law presented requests for jury instructions relating to negligence, however, and a special verdict question was posed on the issue of negligence without objection from the plaintiff.
The judge in his instructions did not define negligence for the jury. On the contrary, he said to the jurors: “[Sjomeone was careless here .... There is no evidence to the contrary, *48 the fact that someone was not careless.” The defendant made a timely objection.
The issue on appeal is whether negligence was a live issue at trial or whether, on the other hand, it had been impliedly waived as a result of the way in which the trial was conducted. See
Dalton
v.
Post Publishing Co.,
No case of which we are aware compels a decision to the contrary. In
Dalton
v.
Post Publishing Co.,
In the present case, apart from the failure of Lo-Law’s attorney to argue the negligence issue, nothing occurred at trial which could have led the judge reasonably to believe the issue was waived. In our view, the judge’s failure to correct his instructions upon objection entitles Lo-Law to a new trial on the negligence issue. Because the finding of proximate cause *49 presumed negligence, and because negligence and proximate cause are so closely intertwined, the causation issue should also be presented again to the jury.
2.
On remand, the issue of prejudicial delay should be considered.
Lo-Law received notice of the plaintiffs claim for the first time seven and one-half years after the plaintiff brought this action against the MBTA and eight and one-half years after the accident, following allowance of the plaintiffs motion to amend her complaint, pursuant to Mass.R.Civ.P. 15(a),
After the jury were impanelled, Lo-Law’s loches defense was discussed at a sidebar conference. The judge firmly refused to permit Lo-Law’s attorney to refer to it at trial. Later in the trial, still precluding discussion of the defense, the judge stated that it should have been raised before trial by a motion to dismiss.
The form in which Lo-Law sought to raise the issue was not correct. A judge may find as a fact that loches exists if there has been unjustified, unreasonable, and prejudicial delay in raising a claim. See
Stewart
v.
Finkelstone,
The plaintiff's tort claim is legal, not equitable, in nature. Moreover, the claim was not barred by the statute of limitations as, under Mass.R.Civ.P. 15(c),
Although generally amendments are liberally allowed, and “the expiration of the period of the statute of limitations [is] a reason for allowing the addition or substitution of a new defendant, rather than a reason for not allowing the amendment[,]”
Bengar
v.
Clark Equip. Co.,
The Massachusetts Rules of Civil Procedure do not set forth the precise way in which the issue should be raised in an action at law. In the past, defendants belatedly brought into litigation without notice have raised the issue of the propriety of the allowance of a motion to amend by a variety of pretrial motions. See, for example,
Wadsworth
v.
Boston Gas Co.,
There are reasons in the present case, in addition to the lack of clear guidance in the rules, why we think Lo-Law should have the opportunity to raise the issue of prejudicial delay by motion on remand to the trial court before retrial of the negligence issue. Lo-Law’s answer provided notice of its intention to raise the issue; the trial took place only five months after Lo-Law was added as a party; and, as a result of this appeal, the opportunity still exists for a hearing before a judge of the trial court on the question of prejudicial delay. 3
*52 Accordingly, the judgment, and so much of the jury’s verdict as established negligence on the part of Lo-Law and proximate cause, are vacated. The special jury verdict, insofar as it established that the bus belonged to Lo-Law, not the MBTA, and the amount of the plaintiff’s damages, may stand. The case is remanded to the Superior Court for further proceedings in accordance with this decision.
So ordered.
Notes
Smith and Zobel state that the merger of law and equity has not affected the substantive rule making loches inapplicable to an action at law. Ibid. Procedurally, of course, equitable defenses may be raised in actions at law. See Reporters’ Notes to Mass.R.Civ.P. 2, Mass. Ann. Laws, Rules of Civ.P. at 21 (Law. Co-op. 1982). Compare G. L. c. 231, § 31, as inserted by St. 1973, c. 1114, § 164.
Lo-Law raises several other issues which do not merit extended discussion. It contends that the judge erred in admitting certain evidence relating to the ownership of bus number 6166. However, counsel for Lo-Law essentially stipulated to ownership in the course of his closing argument. He said: “If you want to waste your time going through the other exhibits regarding transfer of ownership or these records that the MBTA — feel
*52
free to do it. I stipulate to you, and I agree, bus number 6166 — that bus number was in control of Lo-Law on that day in Lowell.” Counsel’s admission is binding on Lo-Law. See
Lucia
v.
Water & Sewer Commrs. of Medford,
