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  <element name="StockIssuedDuringPeriodInLieuOfMilestonePaymentValue" id="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans" id="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan" id="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SubleaseArea" id="zfgn_SubleaseArea" type="num:areaItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SubsequentLicensedProductMember" id="zfgn_SubsequentLicensedProductMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TaxCreditCarryForwardExpirationYearStart" id="zfgn_TaxCreditCarryForwardExpirationYearStart" type="xbrli:gYearItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TaxIncentiveReceivable" id="zfgn_TaxIncentiveReceivable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TaxIncentiveReceivableCurrent" id="zfgn_TaxIncentiveReceivableCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TaxIncentiveResearchAndDevelopmentActivities" id="zfgn_TaxIncentiveResearchAndDevelopmentActivities" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TermLoanAMember" id="zfgn_TermLoanAMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ThirdOfferingPeriodEndDate" id="zfgn_ThirdOfferingPeriodEndDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ThirdOfferingPeriodStartDate" id="zfgn_ThirdOfferingPeriodStartDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFourteenCreditFacilityMember" id="zfgn_TwoThousandAndFourteenCreditFacilityMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFourteenEmployeeStockPurchasePlanMember" id="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandFourteenStockOptionMember" id="zfgn_TwoThousandFourteenStockOptionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandSixStockOptionPlanMember" id="zfgn_TwoThousandSixStockOptionPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UsGovernmentSecuritiesDueWithinOneYearMember" id="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UsGovernmentSecuritiesMember" id="zfgn_UsGovernmentSecuritiesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ValuationAllowanceDeferredTaxAssetChangeInAmountDecrease" id="zfgn_ValuationAllowanceDeferredTaxAssetChangeInAmountDecrease" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ValuationAllowanceDeferredTaxAssetChangeInAmountIncrease" id="zfgn_ValuationAllowanceDeferredTaxAssetChangeInAmountIncrease" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
</schema>





