Nice! I should probably create a Takara Tomy section of the forum now, there are several reviews for this brand now 
Takara T.O.M.Y. bought out (?) Yujin. In fact, these crabs were originally released by Yujin. There were originally 12 figures, then it was re-released by Takara, removing six (including two secrets) and adding four (including two new secrets). I originally bought the complete Yujin set and then later added the Takara figures I was missing (BTW, my hermit crab doesn't have a choice in shells--that must be a Takara addition as well).
The original Yujin set was as follows:
A) spider crab, Macrocheira kaempferi
B) Alaska king crab, Paralithodes camtschaticus
C) red-claw crab, Chiromantes haematocheir
D) blue crab, Portunus trituberculatus
E) coconut crab, Birgus lato
F) red swamp crayfish, Procambrus clarkia
G) hermit crab, Pagurus samuelis (with one shell)
H) anemone hermit crab, Dardanus pedunculatus
I) shrimp, Palaemon paucidens
J) mantis shrimp, Oratosquilla oratoria
K) SECRET A: red swamp crayfish (green form)
L)) SECRET B: Japanese crayfish, Cambaroides japonicas
Takara re-released with the following changes:
1) removed C, H, I, J, K, and L
2) Added the following:
A) fiddler crab, Uca tetragonon (male)
B) slipper lobster, Ibacus cilatus
C) SECRET A: fiddler crab (female)
D) SECRET B: red swamp crayfish (albino)