FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Canaan VII LP   2. Issuer Name and Ticker or Trading Symbol MARINUS PHARMACEUTICALS INC [MRNS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 285 RIVERSIDE AVENUE, SUITE 250 3. Date of Earliest Transaction (Month/Day/Year) 07/29/2016 (Street) WESTPORT, CT 06880 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 07/29/2016   S   24,540 D $ 1.71 (2) 2,145,520 I See Footnote (1)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Canaan VII LP 285 RIVERSIDE AVENUE SUITE 250 WESTPORT, CT 06880		X
Canaan Partners VII LLC 285 RIVERSIDE AVENUE SUITE 250 WESTPORT, CT 06880		X

Signatures

Canaan VII L.P. By: Canaan Partners VII LLC its General Partner By: /s/ Guy Russo, Attorney-in-Fact		08/02/2016
**Signature of Reporting Person		Date
Canaan Partners VII LLC By: /s/ Guy Russo, Attorney-in-Fact		08/02/2016
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Shares held directly by Canaan VII L.P. (the "Canaan Fund"). Canaan Partners VII LLC ("Canaan VII") is the sole general partner of the Canaan Fund and each may be deemed to have sole voting, investment and dispositive power with respect to the shares held by the Canaan Fund. Canaan VII disclaims Section 16 beneficial ownership of the securities held by the Canaan Fund, except to the extent of its pecuniary interest therein, if any.
(2)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.70 - $1.74, inclusive. The reporting persons undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the range set forth in footnote (2) of this Form 4.
Remarks: Exhibit 24 - Power of Attorney

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