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. Author manuscript; available in PMC: 2019 Dec 3.
Published in final edited form as: Dev Dyn. 2013 Oct 7;242(11):1320–1331. doi: 10.1002/dvdy.24021

Table 1.

NRSS Stage Reference Table

Stage
Number
Stage Name OA/D
ratio
Tentacles Tentacle
L/W
ratio
Pharynx Mesentery
L/H ratio
Number of
pleated
mesenteries
Additional Characteristics
0 Open Wound <= 1.5 - - - - - Immediately post-amputation
0.5 - - - - - Dynamic constriction visible around open wound
1 Wound Closed - - - - - Site of closed wound may appear disorganized
1.5 - - - - - Arches begin to inflate
2 Radial Arches - - - - - Radial array of inflated arches; +/− blebs
2.5 Variable Buds may be visible <= 1 a darkening may be visible sub-orally - - +/− blebs
3 Tentacle > 1.5 Clearly defined tentacles > 1 pharynx may be visible sub-orally - -
3.5 Increasing number and length > 2 < 2 0 Increased inflation and transparency
4 Linear Mesentery distinct visible pharynx > 2 No pleating visible, even upon contraction
4.5 <= 4 Increased stimulus reactivity, pleating possibly visible only upon contraction
5 Pleated Mesentery > 4 NRSS complete