The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
BARCLAYS BK PLC CONV ZERO CPN Convertible Bonds 06741JV89 41 46,000 PRN   SOLE 0 46,000 0 0
LAYNE CHRISTENSEN 4.25 CONVERT DUE 11/15/2018 Convertible Bonds 521050AB0 10,931 10,909,000 PRN   SOLE 0 10,909,000 0 0
APPLE INC. Common Stocks 037833100 16,909 74,906 SH   SOLE 0 74,906 0 0
ABB LIMITED Common Stocks 000375204 9,431 399,121 SH   SOLE 0 399,121 0 0
ACCENTURE PLC Common Stocks G1151C101 8,575 50,384 SH   SOLE 0 50,384 0 0
AEGON N.V. ADR Common Stocks 007924103 148 23,000 SH   SOLE 0 23,000 0 0
AMGEN INC Common Stocks 031162100 311 1,500 SH   SOLE 0 1,500 0 0
AMAZON COM INC Common Stocks 023135106 359 179 SH   SOLE 0 179 0 0
NATUS MEDICAL, INC. Common Stocks 639050103 232 6,500 SH   SOLE 0 6,500 0 0
BRISTOL-MYERS SQUIBB CO Common Stocks 110122108 8,352 134,531 SH   SOLE 0 134,531 0 0
BLACK STONE MINERALS LP Common Stocks 09225M101 319 17,529 SH   SOLE 0 17,529 0 0
CELGENE CORPORATION Common Stocks 151020104 16,073 179,602 SH   SOLE 0 179,602 0 0
CHECK POINT SOFTWARE TECH Common Stocks M22465104 12,796 108,744 SH   SOLE 0 108,744 0 0
CISCO SYSTEMS, INC. Common Stocks 17275R102 354 7,272 SH   SOLE 0 7,272 0 0
CHEVRON CORP. Common Stocks 166764100 202 1,650 SH   SOLE 0 1,650 0 0
DISH NETWORK CORP Common Stocks 25470M109 323 9,025 SH   SOLE 0 9,025 0 0
DORCHESTER MINERALS LP Common Stocks 25820R105 919 45,030 SH   SOLE 0 45,030 0 0
DELL TECHNOLOGIES CLASS V Common Stocks 24703L103 19,248 198,183 SH   SOLE 0 198,183 0 0
EBAY INC Common Stocks 278642103 9,099 275,575 SH   SOLE 0 275,575 0 0
ENTERPRISE PRODUCTS PRTNS Common Stocks 293792107 30,836 1,073,296 SH   SOLE 0 1,073,296 0 0
ENERGY TRANSFER EQUITY L P Common Stocks 29273V100 296 17,000 SH   SOLE 0 17,000 0 0
GENERAL ELECTRIC Common Stocks 369604103 206 18,254 SH   SOLE 0 18,254 0 0
GILEAD SCIENCES, INC Common Stocks 375558103 13,877 179,737 SH   SOLE 0 179,737 0 0
ALPHABET INC CL C (GOOGLE C) Common Stocks 02079K107 33,204 27,821 SH   SOLE 0 27,821 0 0
ALPHABET INC CL A (GOOGLE A) Common Stocks 02079K305 20,913 17,325 SH   SOLE 0 17,325 0 0
HONEYWELL INTL INC Common Stocks 438516106 2,082 12,513 SH   SOLE 0 12,513 0 0
INDEPENDENT BANK GROUP, INC Common Stocks 45384B106 369 5,564 SH   SOLE 0 5,564 0 0
INOVALON HOLDINGS INC. (Class A) Common Stocks 45781D101 7,907 786,746 SH   SOLE 0 786,746 0 0
KINDER MORGAN, INC. Common Stocks 49456B101 22,333 1,259,622 SH   SOLE 0 1,259,622 0 0
LAS VEGAS SANDS Common Stocks 517834107 10,377 174,908 SH   SOLE 0 174,908 0 0
MATADOR RESOURCES CO. Common Stocks 576485205 1,487 45,000 SH   SOLE 0 45,000 0 0
NOBLE ENERGY INC Common Stocks 655044105 5,768 184,943 SH   SOLE 0 184,943 0 0
NIELSEN HOLDINGS PLC Common Stocks G6518L108 30,118 1,088,862 SH   SOLE 0 1,088,862 0 0
NVIDIA CORP Common Stocks 67066G104 281 1,000 SH   SOLE 0 1,000 0 0
NXP SEMICONDUCT Common Stocks N6596X109 889 10,400 SH   SOLE 0 10,400 0 0
OWENS & MINOR, INC. Common Stocks 690732102 388 23,500 SH   SOLE 0 23,500 0 0
PAYCHEX INC. Common Stocks 704326107 412 5,600 SH   SOLE 0 5,600 0 0
QUALCOMM INC Common Stocks 747525103 33,829 469,646 SH   SOLE 0 469,646 0 0
SCHLUMBERGER LTD Common Stocks 806857108 2,036 33,413 SH   SOLE 0 33,413 0 0
VISA, INC. Common Stocks 92826C839 660 4,400 SH   SOLE 0 4,400 0 0
WALGREENS BOOTS ALLIANCE Common Stocks 931427108 255 3,500 SH   SOLE 0 3,500 0 0
WESTERN GAS PARTNERS, LP Common Stocks 958254104 240 5,500 SH   SOLE 0 5,500 0 0
EXXON MOBIL CORP Common Stocks 30231G102 276 3,251 SH   SOLE 0 3,251 0 0
XYLEM INC. Common Stocks 98419M100 13,299 166,514 SH   SOLE 0 166,514 0 0