126 Bulletin Vanderbilt Marine Mixseum, Vol. VII 



with the lateral-distal margins convergent and rounded distally. 

 This plate is situated mid-dorsally and overlapping on either side 

 of it are the prominent side arm plates v^rhich project latero-dor- 

 sally and extend distally farther forv^ard than does the related 

 dorsal plate. The side arm plates each bear three short, stout, 

 blunt spines which on the average have the ventral and dorsal 

 spines subequal and the median one the longest and also thickest, 

 being from one-fourth to one-third longer than the other two 

 spines. The ventral plate is a little wider distally than long, with 

 the distal margin widely rounded, the lateral margins con- 

 cave beside the adjacent tentacle scale, and the inner margin of 

 the plate appearing concave because of the overlapping adjacent 

 plate. There are two tentacle scales, the larger one is a broad 

 oval, widely rounded distally. The smaller scale is more tapered 

 distally. 



References: Amphiura ochroleuca, Brock, J., Zeit. f. Wiss. 

 Zool., Leipzig, 1888, Bd. XLVII, p. 485. — Koehler, R., Mem. 

 Soc. Zool., France, Paris, 1904, t. XVII, p. 63, figs. 12-13. 

 (Figures original specimen of Brock.) 



Amphiodia ochroleuca, Clark, H. L., Mem. Mus. Comp. Zool., 

 1915, vol. XXV, p. 250, entry No. 659; Publ. 214, Carnegie 

 Inst., Washington, Dept. Marine Biol., 1921, Vol. X, p. 107. 



Genus: OPHIACTISLutken 

 Ophiactis brocki de Loriol 



i 



Plate 44 



Type : This was collected in Amboina Bay and is deposited in 

 the Geneve Musee d'Histoire Naturelle. 



Distribution : The "Alva" specimens appear to be the first 

 record of this exquisite species since the type and substantially 

 extend the geographic range of this species in the tidal zone, it 

 having been found abundantly in the Society Islands and also 

 taken at Ingham Island, Australia. 



Material examined: Seventeen specimens, Venus Point 

 Reef, Tahiti, Society Islands, August 17, 1931. Two, on coral, 

 Ingham Island, Queensland, Australia, October 12, 1931. 



