Pangenesis and Lamarck's theory of inheritance of acquired characteristics
Pangenesis and Darwin's Gemmules theory suggests a mechanism so that the body's information can travel to and be transmitted by the gametes. Today we know that the information is present in every cell. 

Stephen Gould estimates that Lamarck was the first to develop a truly coherent evolutionary theory.

Lamarck's biological and metaphysical theories comprised entirely correct premonitions, 70 years before Darwin. His book was "Philosophie Zoologique" and Lamarck was not illustrious in his lifetime. His lack of evidence made him an impious, profane author, of the pre-enlightenment style of Voltaire, Rousseau, and prior to Emile Zola and Jules Verne.

Scientists have recently attacked Lamarck with great energy, in favor of Darwin: 
http://www.textbookleague.org/54marck.htm

Basically Darwin emulated Lamarck's skeletal theory, perhaps independently, and fleshed it out in a modern writing style. He also discovered the foundations of an entire scientific field of his own which tied into Lamarck's, and he fought the church and the science institutions with it. 

The evidence of Darwin was copious and meticulous, completing the work of Lamarck (with lesser or greater brilliance, for you to judge).

Lamarck's speciation theories were correct, and his trait-inheritance theory was metaphysical. 

First law 
Life by it's own force, tends to increase the volume of all organs which possess the force of life, and the force of life extends the dimensions of those parts up to a extent that those parts bring to themselves;

Second law
The production of a new organ in an animal body, results from a new requirement arising. and which continutes to make itself felt, and a new movement which that requirement gives birth to, and it's upkeep/maintenance;

Third Law 
The development of the organs, and their ability, are constantly a result of the use of those organs.

Fourth Law
All that has been acquired, traced, or changed, in the physiology of individuals, during their life, is conserved through the genesis, reproduction, and transmitted to new individuals who are related to those who have undergone those changes.

Darwin convinced many scientists and wrote about it continuously from his 30's till his 70's non-stop, sent letters to everyone, and used evidence to define a scientific and mechanical reality to the theory of adaptive radiation. Darwin also coined catchy phrases:

The English and French view of Lamarckism differ. 

The English view slights his status, due to lack of evidence and some alchemical bases for the selection process, even though Lamarck is the father of adaptive radiation theory, in the age of the printed book. 

The French view gives him more influence, firstly because he may have inspired Darwin as an eloquent writer on the topic of adaptive radiation, the father of the adaptive radiation theory, and secondly because a glimmer of Lamarckism can be found in the new discoveries of Epigenetics, non genetic inheritence.