246 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



and Middle Chincha Island, Peru. The last is the farthest south for 

 incisa, 13° 39' 15" S. All stations are in shallow water, less than 50 fms 

 and almost always less than 20, A very small specimen is labeled as from 

 Station 1105-40 in the Gulf of California, with a depth of 113-127 fms. 

 It is probable that this individual was actually dredged at Station 1101- 

 40, but was lost in the meshes of the dredge until the careful search after 

 a deep water haul. It is notable that no specimens of incisa were taken at 

 the Galapagos Islands, Cocos, Clarion or Socorro Islands, nor along the 

 Costa Rican coast, though it has been previously recorded from the 

 Galapagos. 



Type.— M.C.Z. no. 467 (Cotype). 



Type locality. — Guaymas, Lower California, Mexico. 



Depth. — Shore to 50 fms. 



Specimens examined. — 1,121 specimens from 82 stations. 



Arbacia spatuligera (Valenciennes) 

 Plate 40, Fig. 12 



Echinus (Agarites) spatuliger Valenciennes, 1846, pi. 5, fig. 2. 

 Arbacia spatuligera A. Agassiz, 1872a, p. 93. 



H. L. Clark, 1910, p. 346, pi. 10, fig. 2. 

 Mortensen, 1935, p. 577, pi. 70, figs. 1-5. 



Adult specimens of this rather handsome sea-urchin are said to reach 

 a test diameter of 70 mm but the finest of the 15 specimens secured by the 

 Velero are barely 50 mm h. d. and the longest spines scarcely exceed 40 

 mm. These large specimens (30-50 mm h. d.) are brown, very dark on 

 the test but with the spines much lighter, a real fawn brown. Small speci- 

 mens (15-25 mm h. d.) are dark; the smaller has the interambulacra 

 definitely tinged with green and the spines are dull pink or rose, brightest 

 on the lower surface; the larger (25 mm h.d.) has the dark interambula- 

 cra scarcely tinged with green and the primary spines dark violet. A series 

 of 5 very small Arbacias from Sechura and Independencia Bays, Peru, 

 are pale gray or whitish or reddish brown, with the primary spines either 

 colorless or with one or two light red bands. While it is not certain that 

 these little Arbacias are young spatuligera, there is little reason to doubt it. 



Distribution. — Even including the very small Arbacias just men- 

 tioned, the Velero material throws no new light on the distribution of 

 spatuligera. The largest specimens are from San Lorenzo Island, Peru in 

 5 fms. The remaining material is from Sechura and Independencia Bays 

 in water 10 fms deep or less. So far as the Velero collections are concerned 

 this Arbacia is found only in Peru. 



