Morphology and ultrastructure of digestive system in pre-zoea and zoea I larvae of red king crab, Paralithodes camtschaticus (Tilesius, 1815).

The digestive system structure in pre-zoea and zoea I larvae of the red king crab Paralithodes camtschaticus has been examined. During this development period, the digestive system consists of an esophagus, a stomach, a midgut (where the hepatopancreas ducts open), and a hindgut. The esophagus begins from the oral slit on the animal's ventral side and extends vertically up to the junction with the cardiac stomach.

Muscle Regeneration in Holothurians without the Upregulation of Muscle Genes.

The holothurian is capable of fully restoring its muscles after transverse dissection. Although the regeneration of these structures is well studied at the cellular level, the molecular basis of the process remains poorly understood. To identify genes that may be involved in the regulation of muscle regeneration, the transcriptome of the longitudinal muscle band of has been sequenced at different time periods post-injury.

Development of respiratory trees in the holothurian Apostichopus japonicus (Aspidochirotida: Holothuroidea).

The development of respiratory trees in the holothurian Apostichopus japonicus has been studied using light and electron microscopy. Primordial respiratory trees emerge in 2-3-mm-long animals (2 months after fertilization). They arise as two independent outgrowths from the dorsal wall of the anterior part of the cloaca.

Post-autotomy regeneration of respiratory trees in the holothurian Apostichopus japonicus (Holothuroidea, Aspidochirotida).

Specialised respiratory organs, viz. the respiratory trees attached to the dorsal part of the cloaca, are present in most holothurians. These organs evolved within the class Holothuroidea and are absent in other echinoderms.