NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 245 



tip of the extended spines it measures 120 mm. Mortensen refers to the 

 "largest size recorded for this species is 60 mm diameter" but he does 

 not give his authority for this giant.^ Only a very few of the Velero's 1,121 

 specimens exceed 35 mm h. d. (the largest is 56) and a very large number 

 are less than 20 mm across. Veiy young specimens (2-8 mm h. d.) are as 

 a rule light colored more or less flesh red, becoming red brown, or violet 

 or deep purple, until finally they are nearly or quite black. A few dry 

 specimens are more or less definitely gray. One curious variety has some 

 of the primaries, or at least portions, quite pink or white in striking con- 

 trast to the black of the remaining spines and test. Mortensen (p. 566) 

 makes the "conspicuous red spots in the interambulacra on the aboral 

 side" the distinguishing mark of the species and the Velero collection con- 

 firms his judgment. Even in the most nearly black adults, careful examin- 

 ation in good light will show at least faint indications of the tell-tale red 

 blotches. Young individuals with the test flesh color or red and the red 

 spines with one or more whitish bands are so different from the more 

 mature specimens, it is hard to believe they can ever become as dark 

 colored as they do, but the present large series compels the acceptance of 

 the fact. In one or two of the very black specimens there is real difficulty 

 in seeing any red, but such individuals cannot be distinguished satis- 

 factorily as anything other than excessively pigmented incisa. 



Mortensen's (1935, p. 577) plea for the specific name stellatus is 

 inadequate, and if we once let such arguments control our decisions we 

 shall have more disagreements and resulting confusion than we have had 

 hitherto. Nobody knows to what sea-urchin the name stellatus was first 

 given. Everyone knows what Echinocidaris incisa was at the start and 

 there has never been any confusion about it, so I have no hesitation in 

 continuing the use of the name here. 



Distribution. — The Velero collections show that this is essentially a 

 species of the Gulf of California. It ranges north to the southern United 

 States as shown by Ziesenhenne (1941, pp. 117-120). There are 6 very 

 fine adult specimens in the Velero collection from Newport Harbor, 

 California, but the Velero has taken no other specimens north of Lower 

 California, nor along its western coast. South of the Gulf, incisa does not 

 appear to be very common though there are specimens at hand from Bahia 

 Honda, Panama; Gorgona Island, Colombia; Santa Elena Bay and La 

 Plata Island, Ecuador; Zorritos Light, South Bay, Lobos de Afuera, 



4 The authority for this giant is Clark himself, who says in his Echinoderms of 

 Peru, p. 345, that "large specimens may be 60 mm in diameter." Th. Mortensen 



