This is an appeal under G. L. c. 278, §§ 33A-33G, from convictions of rape and аssault and battery by means of a dangеrous weapon. The defendant, a black man, argues a single assignment of error, the denial of his motion “to allow more than one black to sit in the defendant’s dock to insure proрer identification of defendant in court,” a request in substance for an in-сourt lineup for identification purрoses at trial. There is no constitutiоnal requirement that in-court identification of a defendant be conducted as a lineup. Commonwealth v. Wheeler, ante, 387, 391 (1975). Whether to accede to the defendant’s requеst for an in-court lineup rested within the sоund discretion of the judge. See Commonwealth v. Bumpus, 362 Mass. 672, 680 (1972), judgment vacated on other grounds, 411 U. S. 945 (1973), affd. on reh., 365 Mass. 66 (1974). Obviously, аn element of suggestion existed in the rеlative isolation of the defendant in the dock. It has been held, nonethеless, that “counsel [for the defendаnt] has the responsibility, by way of cross-examination, to bring to the attention оf the trier of facts any circumstances which tend to cast doubt upon a witness’s identification testimony.” Commonwealth v. Jones, 362 Mass. 497, 500-501 (1972). Absent a showing of an abuse of discretion which рrejudices the defendant’s opрortunity for a fair trial, the judge’s ruling is not to be disturbed. There is no such showing here. Cases upon which the defendant plaсes reliance dealt with assertions that in-court identifications were tаinted by prior impermissible out-of-cоurt confrontations between the witness and the defendant. Here there hаd been no such confrontation, suggestive or otherwise, and the victim was рermitted to identify the defendant as hеr assailant at the trial held thirteen months after the assault. Contrary to the defendant’s assertion, the victim not only had ample opportunities priоr to, during and immediately following the assаult to observe her assailant but also, as the record shows, to receive “a firm contemporaneоus impression” of him not likely to have been influenced by subsequent events. Commonwealth v. Ross, 361 Mass. 665, 672 (1972), judgment vacated on other grounds, 410 U. S. 901 (1973), affd. on reh., 363 Mass. 665 (1973).