Hi Alexey – Here are a couple.  Cheers – Gustav

Stricker, Stephen A. "The ultrastructure and formation of the calcareous ossicles in the body wall of the sea cucumber Leptosynapta clarki (Echinodermata, Holothuroida)." Zoomorphology 105, no. 4 (1985): 209-222.

Stricker, Stephen A. "The fine structure and development of calcified skeletal elements in the body wall of holothurian echinoderms." Journal of morphology188, no. 3 (1986): 273-288.

From: flmnh-aspidolist [mailto:[log in to unmask]] On Behalf Of ??????? ???????
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Dear Colleagues,

I would be very grateful for bibliographic references about holothurian spicules formation and development.

Thanks in advance,

Alexey