Juana R. Vda. del Rosario  is the  widow  and  Manuel del Rosario and Luis del Rosario are the  children by the second marriage of the  late Simplicio  del Rosario.  On 20 August 1954 the Government brought an action in the Court of First Instance of Manila against the above-named persons to collect from them a balance of P7,622.74, for 1946 deficiency  income tax  amounting to P14,097.54 due from their late  husband and father Simplicio  del  Rosario who died 22  February  1947 leaving  an estate valued at P196,147.06 which the defendants and the children by the first marriage inherited.  The complaint  alleges  that the defendants and  their co-heirs are liable to pay the deficiency income tax due from their predecessor  in proportion to their share in his  estate; that their co-heirs already had paid fully their respective shares in  the deficiency income tax due from them but the  defendants had paid  only the sum of P6,286.60, thus leaving a balance of P7,622.74 still unpaid,  which  they refused to  pay  notwithstanding  repeated demands.  The plaintiff prays that the defendants be ordered to pay to the Government the aforesaid balance, delinquency penalties and lawful interest due thereon from the date of the filing  of the complaint and costs.  It further prays for any other just and equitable  relief (civil No. 23783).

The defendants moved for the dismissal of the complaint on the ground that it states no cause of action and that it is barred by the statute of limitations.   After their motion had been denied, they answered the complaint admitting payment by  them of P6,286.60  and their refusal to pay the balance of P7,622.74 and setting up the special defense that since the children by the first and second marriages received equal  shares in the  estate of the deceased,  the defendants  alone  should not be  held liable for the total amount sought to be collected by the plaintiff.  They prayed that the complaint be dismissed or  that  the  children by the first marriage  be  impleaded as third party defendants in the case.

On 14 April  1955  the plaintiff filed a  motion  praying that the case be certified  to the Court of Tax  Appeals pursuant to section 22 of  Republic  Act No.  1125.  After hearing, the Court denied the motion. On 21 April, after further study of the  question  raised by the plaintiff the Court set aside  its previous order and certified the case to the Court of Tax Appeals giving as ground for the reversal the fact that the case  involved a disputed assessment made by  the  Collector of Internal Revenue.  On 21 November the Court  of Tax  Appeals resolved  that as the complaint was filed on 20 August 1954, or after the enactment of Republic Act No. 1125 creating the Court of Tax Appeals, it had no jurisdiction over the case  and returned it to the Court of First  Instance.   On 9 February 1956 the  Court of First Instance dismissed the case without prejudice,  it being of the opinion that as it involved a disputed assessment made by the Collector of Internal Revenue,  the case was within the jurisdiction of the Court  of Tax Appeals.

The plaintiff has appealed.

The question  now is which court has jurisdiction to hear and determine  the case, the Court  of  First Instance as. contended  by the  appellant or the Court of Tax Appeals as maintained by the appellees?

The  pertinent  provisions of  Republic Act No.  1125 provide:

SEC.  7. Jurisdiction. The Court of Tax Appeals shall exercise exclusive appellate  jurisdiction  to  review by  appeal, as  herein provided

(1) Decisions of the Collector of Internal Revenue in cases involving  disputed  assessments,  refunds of  internal revenue  taxes,. fees or other charges, penalties imposed in relation thereto, or other matters  arising under the National Internal Revenue Code or other law or part of law administered by the Bureau of Internal Revenue;
(2)  *    *   *
(3)  *    *   *

SEC. 11.  Who may appeal; effect  of  appeal. Any  person,  association or corporation adversely affected by a decision or ruling of the Collector of Internal Revenue, the  Collector of Customs or any provincial or city Board of Assessment  Appeals may file an appeal in the Court of Tax Appeals within thirty  days after the receipt of such  decision or ruling.

SEC.  22. Pending cases  to be remanded to Court. All cases  involving disputed assessment of Internal Revenue taxes  or customs duties pending determination  before the  Court of  First Instance shall be  certified and remanded by the respective  clerk of  court to the  Court of Tax Appeals for  final disposition thereof.

The Solicitor General points out that the case was filed on 20 August 1954, after Republic Act No. 1125 took effect (16 June 1954).  He  argues  that the case  was  not then pending determination in the Court of First Instance at the time of the  approval of Republic Act No. 1125;  and that it is not a case involving a disputed assessment of internal revenue tax or  customs duties, but an original action to enforce payment of income tax due.   Hence he concludes that the Court of Tax Appeals has no jurisdiction to hear and determine the case.

Section 7, Republic  Act No. 1125, vests in the Court of Tax Appeals exclusive appellate jurisdiction  to review by appeal "Decisions of the Collector of  Internal Revenue in cases  involving disputed assessments, refunds of internal revenue taxes, fees or other charges, penalties imposed in relation  thereto,  or  other  matters  arising  under  the National Internal Revenue Code or other law or part of law administered by the Bureau of Internal Revenue;" and section  11 of the same Act provides for an appeal by those who are adversely affected by a decision or  ruling of the Collector of Internal Revenue  to the Court of Tax Appeals within thirty  days after receipt of the decision or ruling. Obviously, the case of the appellees  does not come  under section  7 of the Act, because they have not appealed from the assessment made by the Collector of Internal Revenue, as provided for in section 11 of the Act.  And their failure to appeal from the assessment rendered it final, executory and demandable.  Their refusal to pay the balance of the 1946 deficiency income tax due from their late father  after paying partially does not render the assessment a disputable one.

The order appealed  from is  reversed and the  case  remanded to  the Court  of  First  Instance of Manila for further proceedings in accordance with law, without pronouncement as to costs.

Paras,  C. J.,  Bengzon, Reyes, A., Bautista Angelo, Labrador, Concepcion,  Reyes, J. B. L., and Endencia, JJ.,concur.