1920] Kew: Cretaceous and Cenozoic Echinaidea 



69 



SCUTELLA GABBI (Reinond) 

 Plate 12, figures 4a, 46; plate 13, figures 1, 2a, 2b, 3 



Clypeaster gabhi Eemond. Proc. Calif. Aead. Sei., vol. 3, 1863, pp. 53-54. 

 Clypeaster gahbi. Meek, Sinithson. Misc. Coll., vol. 7, no. 183, 1864, p. 2. 

 Clypeaster gahbi. Gabb, Geol. Surv. Calif. Pal., vol. 2, 1869, pp. 36, 109, 



pi. 12, figs. 64, 64o. 

 Clypeaster gahbi. Cooper, Cat. Calif. Fossils, Seventh Ann. Eept. Calif. 



State Mineralogist, 1888, p. 27. 

 Scutella (Clypeaster) gabhi. Merriam, Univ. Calif. Publ. Bull. Dept. Geol., 



vol. 2, 1898, pp. 110, 111, 113, 114, 117. 

 Scutella gabhi. Merriam, Proc. Calif. Acad. Sci., ser. 3, Geol., vol. 1, 1899, 



p. 168, pi. 22, figs. 5, 5a. 

 Echinarachnius gahbi. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 703. 

 Scutella gahbi. Kew, Univ. Calif. Publ. Bull. Dept. Geol., vol. 18, 1915, 



pp. 366-368, pi. 39, figs. 1-3. 

 Scutella gahbi. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, 



p. 189, pi. 88, figs, la, lb. 

 Clypeaster ? gabbi. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 



1915, p. 211. 



Neotype.— 'No. 11001 Univ. Calif. Coll. Invert. Pal. 



Test small. Average measurements: anteroposterior diameter 25.3 

 mm., transverse diameter 26.3 mm., greatest height 6.3 mm. Outline 

 circular to subcircular, subpentagonal in some specimens ; transverse 

 diameter often greater than the anteroposterior diameter ; very faintly 

 notched at the ambitus in the posterior ambulacral areas. Upper sur- 

 face depressed, with margin rather thin but having a tendency to be 

 thicker in young forms. Summit usually anterior to the apical system, 

 which is slightly eccentric anteriorly. Pour large genital pores present, 

 the one opposite the posterior interambulacral area being absent ; five 

 small radial plates, each possessing a pore. Petals usually unequal 

 in length ; those of the trivium extend nearer to the margin than those 

 of the bivium ; posterior lateral pair longest, the anterior laterals 

 shortest, with the odd petal usually intermediate or about as long as 

 the posterior pair. Petals open at their ends; odd anterior one wide 

 open. Inner rows of pores of lateral pairs of petals in almost straight 

 lines, converging very slightly toward the end ; outer rows converge 

 to a greater degree, which in most specimens almost close with the 

 inner rows at the distal end of the petal. Pairs of small pores continue 

 to the margin, the pairs diverging from each other to a marked degree. 

 Each poriferous area of about the same width as the interporiferous 

 area, except in the odd anterior petal, where they are about one-half 

 the width. Ambulacra widen rapidly from the ends of the petals to 



