Supreme Court explained in People v. Daniels (1975) 14 Cal. 3d 857, 860 [122 Cal. Rptr. 872, 537 P.2d 1232], " 'when the definition of a crime consists of only the description of a particular act, without reference to intent to do a further act or achieve a future consequence, we ask whether the defendant intended to do the proscribed act. This intention is deemed to be a general criminal intent. When the definition refers to defendant's intent to do some further act or achieve some additional consequence, the crime is deemed to be one of specific intent.' [Citation.]" (Quoting People v. Hood (1969) 1 Cal. 3d 444, 456-457 [82 Cal. Rptr. 618, 462 P.2d 370].) Generally, a mistake of law is not a defense to a general intent crime, but in some circumstances it may be a defense to a specific intent crime. (1 Witkin & Epstein, Cal. Criminal Law, supra, 218-219, pp. 251-253.) "A trial court's duty to instruct, sua sponte, or on its own initiative, on particular defenses . . ., arises 'only if it appears that the defendant is relying on such a defense, or if there is substantial evidence supportive of such a defense and the defense is not inconsistent with the defendant's theory of the case." ( People v. Barton (1995) 12 Cal. 4th 186, 195 [47 Cal. Rptr. 2d 569, 906 P.2d 531].)