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PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



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Figure 3. — Henricia eschrichti: a, aboral ray plates; b, aboral ray spines; c, adambu- 

 lacral spines, showing variable 1-row pattern; d, adambulacral and marginal spines, 

 showing comblike arrangement of the marginals. 



by spaces equal to their own diameter or larger, transverse combs of 

 spines on the marginal plates, with the inframarginals the larger, 

 madreporite with obvious rows of spines, occasionally 2 rows of blunt 

 adambulacral spines per plate, and almost always a single spine (the 

 largest one of the series) at the upper edge of the adambulacral 

 groove. It differs from pectinata in having some dorsal paxillae with 

 as many as 12 to 14 spines, most inframarginal plates with fewer 

 than 20 spines, and adambulacral plates usually with only 5 or 6 

 (rather than 8 to 12) spines in only 1 row or in irregular zigzag rows. 

 The last feature probably is the most important — compare figure 3 



