disturbed, or youthful offenders, classified and defined as follows, shall be coordinated by the Department of Social Welfare: 1. A child-caring institution is one that provides twenty-four resident group care service for the physical, mental, social and spiritual well-being of nine or more mentally gifted, dependent, abandoned, neglected, handicapped or disturbed children, or youthful offenders. 2. An institution, whose primary purpose is education, is deemed to be a childcaring institution when nine or more of its pupils or wards in the ordinary course of events do not return annually to the homes of their parents or guardians for at least two months of summer vacation. 3. A detention home is a twenty-four hour child-caring institution providing short term resident care for youthful offenders who are awaiting court disposition of their cases or transfer to other agencies or jurisdiction. 4. A shelter-care institution is one that provides temporary protection and care to children requiring emergency reception as a result of fortuitous events, abandonment by parents, dangerous conditions of neglect or cruelty in the home, being without adult care because of crisis in the family, or a court order holding them as material witnesses. 5. Receiving homes are family-type homes which provides temporary shelter from ten to twenty days for children who shall during this period be under observation and study for eventual placement by the Department of Social Welfare. The number of children in a receiving home shall not at any time exceed nine: Provided, That no more than two of them shall be under three years of age. 6. A nursery is a child-caring institution that provides care for six or more children below six years of age for all or part of a twenty-four hour day, except those duly licensed to offer primarily medical and educational services. 7. A maternity home is an institution or place of residence whose primary function is to give shelter and care to pregnant women and their infants before, during and after delivery. 8. A rehabilitation center is an institution that receives and rehabilitates youthful offenders or other disturbed children. 9. A reception and study center is an institution that receives for study, diagnosis, and temporary treatment, children who have behavioral problems for the purpose of determining the appropriate care for them or recommending their permanent treatment or rehabilitation in other child welfare agencies. 10. A child-placing agency is an institution or person assuming the care, custody, protection and maintenance of children for placement in any child-caring institution or home or under the care and custody of any person or persons for purposes of adoption, guardianship or foster care. The relatives of such child or