442 STRONGYLOCENTROTUS FRANCISCANUS. 



than in S. depressus. Cuts of actinostome very moderate. Color of spines 

 olive-brown ; they are moderately stout, tapering, tipped with violet. 

 Buccal membrane thin, strengthened in the continuation of the ambulacra 

 by a few elliptical plates. 



In young specimens the difference in size of the tubercles between the two 

 areas is not so marked, and in large specimens the median vertical lines 

 become regular vertical rows of secondary tubercles. 



A young specimen of this species was marked in the Jardin des Plantes 

 as labelled by Lamarck " E. tuberculatus " with a larger specimen, which 

 would leave no doubt as to which species was intended to be named S. 

 tuberculatus; to prevent confusion the large specimen was taken as the 

 type of Lamarck, and the other names given to the species of this genus 

 adopted to correspond to this assumption. 



Diameter Diamctci Dian eter Wi.Ith 

 Ibacl Syet Act. Syst. Anal. Sysl Porif.Zone. 



II. 21. 0. 4.8 



II. 18.8 5.6 



8.2 1G. 3.5 



8.1 13.0 4. 2.4 



Australia ; Tasmania : San 



Strongylocentrotus franciscanus 



IToxocidaris franciscana A. A<;.. ISO.'!. Bull. M. ('. '/... I. 



I s rongylocentrotus franciscanus A. A.G., 1872, Rev. Ech., l't. I. p. 163. 



PI V'.f. 1-2; PI. VI. f. in, in'. 



This large species is readily distinguished from its congeners by its high 

 coronal plates; it is more closely allied to the Sandwich Island species. 

 S. nudus, than any other. The striatum of the spines is extremely fine, and 

 the transverse grooving scarcely marked ; while in the Sandwich Island 

 species the striatum of the spines is coarse and the transverse grooving more 

 marked. In addition to this, specimens of S. nudus having already thirteen 

 coronal plates are much smaller than specimens of S. franciscanus with 

 an equal number of plates ; unfortunately the specimens from the two local- 

 ities are so different in size that a close comparison could not lie instituted, 

 and I can only call attention to the relationship of these two species at the 

 present time, and point out their differences. Since the number of Echino- 

 derms common to Northern Japan and the coast of California is by no 

 means inconsiderable, it would not be at all unlikely if further materials 

 should prove the identity of these two species. Other points of difference 



