Collection National Maritime Museum, Greenwich, London.                                                                                     
The Ship's Company of HMS Beagle was painted by Augustus Earle around 1833. It shows the Sunday bible reading in the gunroom (see canon on left). The officers on board were Lt. Robert Fitzroy (Captain), John Wickham (1st Lt.), James Sulivan (2nd Lt.) Robert McCormick (surgeon), Benjamin Bynoe (assistant surgeon) George Rowlett (purser) & Midshipman King. Alexander Burns Usborne has not yet been spotted, nor is Charles Darwin obvious. The oldest man on board was 37 (Rowlett) and the average age around 25. Alexander was 25 as was Darwin; Fitzroy was 28. The total number on board was 74, all of whom are shown here. The Beagle was a ten gun Brig of 242 tons and 90 feet in length.

Notes from National maritime museum:

The artist used his numerous watercolour sketches made on board HMS 'Hyperion', during a voyage to Australia in 1820, and his later journey, as official artist in the' Beagle', with Darwin. Some of the figures may be portraits observed on those voyages. The cramped ship-board service has provided this opportunity for close observation and detail. The service takes place on the gun deck above, with daylight visible through the hatches. A capstan runs vertically through the centre of the image, and the companion ladder is empty. There is a clear division between the Navy to the left and marines to the right. An admiral, wearing a pig-tail, looks at a book at a table covered with a flag, sitting on a chair draped with the union flag. In front of him a midshipman possibly reads a lesson from the Bible, attended to in varying degrees by the assembly. There are five figures behind the Admiral's table. A naval officer far right, a hand in his pocket, turns away from the assembly and his smile invites the viewer to question the content of his book. Behind him a fellow officer, feet resting on a cannon, appears to sleep. To his right, a marine colonel catches the eye of another marine officer standing on the far right, and at his feet a small midshipman sits on a stool holding one bible while another lies unopened on the deck. In the foreground to the right, a naval officer appears to be asleep, with an open picture book resting on his lap, and a hat lies discarded nearby. Other naval officers are seated facing the admiral apparently in various attitudes of boredom and, in the background, one sailor seems to have been chastised for inattention by a naval officer bearing a stick. On the right, none of the seated marines, with attitudes varying from attending to yawning, holds a book. One woman, her arms folded, is portrayed in the front row. A military drum is suspended above the marines' heads. The impression of cramped space is accentuated by the sick man in the cradle, his head propped in his hand as he reads from the open book, immediately above the marines. A figure visible only by the top of his head may be a prisoner. Various objects hang from the bulkheads and beams, baskets of cannon balls, axes, a slate, hourglass, lantern and key. The two parrots are enclosed in their cage and underscore the sailors' and marines' enforced predicament and duty, since religion played little part in a seaman's life. Exhibited at the Royal Academy in 1837.

Julian comments: There were no admirals on board. The officer with the pigtail must be lieutenant Fitzroy.
I believe (without proof) that Alexander was second from the left.