Besides Meriwether Lewis and Capt. William Clark of course...
1.) Sergeant Charles Floyd
2.) Sergeant Patrick Gass
3.) Sergeant Nathanial Pryor
4.) Sergeant John Ordway
5.) Corporal Richard Warfington
6.) Private John Boley
7.) Private William Pratton
8.) Private John Collins
9.) Private John Colter
10.) Private Pierre Cruzatte
11.) Private John Dame
12.) Private Joseph Fields
13.) Private Reuben Fields (Joseph's brother)
14.) Private Robert Frazer
15.) Private George Gibson
16.) Private Silas Goodrich
17.) Private Hugh Hal
18.) Private Thomas Proctor Howard
19.) Private Francois Labiche
20.) Private Jean Baptiste LePage
21.) Private Hugh McNeal
22.) Private John Newman
23.) Private John Potts
24.) Private George Shannon
25.) Private John Shields
26.) Private John B. Thompson
27.) Private Howard Tunn
28.) Private Ebenezer Tuttle
29.) Private Peter M. Weiser
30.) Private William Werner
31.) Private Isaac White
32.) Private Joseph Whitehouse
33.) Private Alexander Hamilton Willard
34.) Private Richard Windsor
35.) Toussaint Charbonneau (Sacagawea's husband)
36.) Sacagawea
37.) Jean-Baptiste Charbonneau (Sacagawea's son)
38.) George Drouillard
39.) York (Clark's slave)
40.) "Seaman" or "Scannon", Lewis' large black Newfoundland dog
The Corps of Discovery was the group of people who accompanied Lewis and Clark through the Louisiana Purchase and the Oregon Territory. The Corps of Discovery consisted of 45 men including York (a slave), and Sacagawea.
I think there were about 10 thousand men in his corps.
There is not a specified number, but is usually three or more divisions and about 60,000 men.
Ira Hayes of the Pima Tribe from Arizona, joined the US Marine Corps in August '42. Hayes is one of the six men who raised the flag at Iwo Jima in 1945.
2
A US Army group is made up of several corps and has 80,000 - 200,000 men
Usually the men on the Expedition got to name animals. Usually the man who found the or caught the animal was able to name it, but sometimes the naming was offered to another man.
100,000
Captains Meriwether Lewis and William Clark lead a group of men called the "Corps of Discovery" to explore the Louisiana Territory from 1804 to 1806.
George Harrison was welcomed to The Quarry Men as a guitarist and played under many names.
A corps is two or more divisions. Frequently in the armies of both sides in WWI a corps had three divisions, but it could have more, There is no set number, just however many divisions seems best to the army commander. (A field army is two or more corps). So the answer depends on the size of the divisions fielded by the country of whose army the corps is a part. British, French and German divisions were around 12-15,000 men at full strength. US divisions of WWI were huge, more than 26,000 men. So, a US corps with only two divisions was bigger than any other nation's corps with three.
No need exists. For some who have joined it was an impulsive moment. Judges were helpful at times by providing the Corps as an alternative to long term incarceration. Thousands became Marines either to avoid the draft or were drafted into the Marine Corps. Some had special skills and were actively enticed into enlistment. Some had been jilted, some were escaping from paternity suits, some were simply hungry and yes there were some who joined because of glitzy advertising, fancy uniforms and because their buddy thought of it first. Professional soldiers have sought out the Corps, and then there have also been hundreds of thousands of young, patriotic men who joined to serve their country.