NO. 4 ziesenhenne: new eastern pacific sea stars 209 



about as wide as long; the width is variable, often a broad spine opposing 

 a narrow spine. They are convex on the outer side and concave on the 

 furrow side, often with a narrow, distinct groove. The subambulacral 

 row is composed of large, robust, spatulate, blunt-tipped spines, longer 

 than wide, about four times as long and twice as wide as the furrow 

 spines. Between the subambulacral spines are slightly enlarged granules, 

 arranged in 1 or 2 series, transversely to the furrow. The mouth plates 

 bear a prominent, enlarged, triagonal, apical oral spine, 2 oral marginal 

 spines, and a prominent, spatulate suboral spine. Granulations on the 

 proximal half of mouth plates small; distal of the suboral spine they be- 

 come enlarged and spatulate. 



Alveolate pedicellariae on the abactinal surfaces; although lacking on 

 the actinal surface of the holotype, they are abundant on the paratype. 

 The distribution of pedicellariae, however, is of no specific importance. 

 Abactinally the pedicellariae are well distributed ; actinally they are con- 

 fined to a single series of 7 to 14 along the subambulacral spines; in sev- 

 eral cases the pedicellariae have replaced the subambulacral spine on the 

 adambulacral plate. The shape of the jaws varies from slightly bent to 

 bifid ; they are thin, flaring widely at the tips and constricted at the base — 

 some flare out widely and are notched to form a letter Y, while others 

 flare asymmetrically to form a letter L. The majority resemble small 

 socks. The sockets in which the pedicellariae lie are straight; the concavity 

 and broad ridge of the socket face the ambulacra. 



The madreporite is 2.3 mm. in diameter and is located interradially 

 about its own diameter from the center of the disk. The surface is covered 

 with fine, close convolutions and striations that radiate from the center. 

 The anal aperture in the center of the disk is closed by 6 long, narrow 

 spinelets, longer than wide and a number of elongated granules. 



Color. — Dried from alcohol, light bufif with a faint lavender hue. 



Types. — Holotype AHF no. 42; one paratype. 



Type locality. — Station 780-38, 40-47 fms., Chatham Bay, Cocos Is- 

 land, Costa Rica, January 14, 1938. One paratype from Station 183-34, 

 50-70 fms., James Bay, James Island, Galapagos, January 24, 1934. 



Remarks. — The paratype measures R=54 mm., r^lO mm., R=5 r. 

 It has fewer papular areas, which are not continuous but alternate with 

 the plates. The alveolate pedicellariae of the actinal surface are more 

 abundant, 7 to 14; abactinal surface, 12 to 15. The anal aperture is closed 

 by 8 small, triangular granules of different sizes. The groove on the fur- 

 row spines is deeper and conspicuous. 



