Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
2018–19 Hull City A.F.C. season
Table title:
Loans in
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Start date </th><th colspan=1 rowspan=1 > Position </th><th colspan=1 rowspan=1 > Nationality </th><th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > From </th><th colspan=1 rowspan=1 > End date </th><th colspan=1 rowspan=1 > Ref. </th></tr>
<tr> <td colspan=1 rowspan=1 > 17 July 2018 </td><td colspan=1 rowspan=1 > RB </td><td colspan=1 rowspan=1 > England </td><td colspan=1 rowspan=1 > Todd Kane </td><td colspan=1 rowspan=1 > Chelsea </td><td colspan=1 rowspan=1 > 31 May 2019 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 31 August 2018 </td><td colspan=1 rowspan=1 > CB </td><td colspan=1 rowspan=1 > England </td><td class="highlighted"  colspan=1 rowspan=1 > Tommy Elphick </td><td class="highlighted"  colspan=1 rowspan=1 > Aston Villa </td><td colspan=1 rowspan=1 > 29 December 2018 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 31 August 2018 </td><td colspan=1 rowspan=1 > CF </td><td colspan=1 rowspan=1 > Scotland </td><td class="highlighted"  colspan=1 rowspan=1 > Chris Martin </td><td class="highlighted"  colspan=1 rowspan=1 > Derby County </td><td colspan=1 rowspan=1 > 31 May 2019 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 22 January 2019 </td><td colspan=1 rowspan=1 > LW </td><td colspan=1 rowspan=1 > England </td><td colspan=1 rowspan=1 > Marc Pugh </td><td colspan=1 rowspan=1 > Bournemouth </td><td colspan=1 rowspan=1 > 25 April 2019 </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
Which players joined in August 2018?
Answer:
On August 31, 2018, Tommy Elphick joined from Aston Villa and Chris Martin joined from Derby County.