510 ECHIXANTHIDAE. 



ECHINANTHIDAE. 

 Subfamily Echinanthidae A. Ac, 1872, Rev. Ech., Pt. II. p. 306. 



This subfamily comprises large species, with pillars or needle-like projec- 

 tions connecting the two floors, with straight ainbulacral furrows ; jaws 

 articulating upon two auricles, the petals having a great degree of develop- 

 ment. 



CLYPEASTER. 



Clypeaster LAMK., 181C, An. s. Vert. (Mull, ememl.) 

 (See Part II. p. 30C.) 



Clypeaster humilis 



! Echinanthu» humile Leske, 1778, Kl. Add.. /'/. XIX. f. A B. 

 ! Clypeaster humUis A. Ac, 1872, Rev. Ech., Pt I. ]>. 100. 



Pl.Xl'.f. 1-8. 



This species is distinguished by its long odd anterior ambulacra! petal, and 

 the great width of the poriferous zone at the extremity of the petals. The 

 petals are usually closed ; poriferous furrows crowded at extremity of petals ; 

 they are characterized by their uniform breadth, and somewhat swollen me- 

 dian tubcrculiferous part rising above the poriferous zone. The pores of the 

 poriferous zone are large, — larger than in the other species of the genus ; the 

 outer pore especially is of great size. The genital openings are distant. The 

 tubercles of the upper part of the test are somewhat smaller than in the 

 West India species. On the actinal side the tubercles increase in size towards 

 the actinostome, and become quite large, especially near the median inter- 

 ambulacral space ; the space occupied by the miliaries between the primary 

 tubercles is wider than in the West India species. In a very large specimen 

 (C. latissimus), measuring 245""", the edge is extremely attenuated; the 

 outline still more undulating than in smaller specimens, but not pentagonal, 

 as is so frequently the case in the West India species. The proportions of the 

 petals in the rosette are not changed in this large specimen ; the median 

 ambulacra] space is less swollen, and the petals somewhat pointed ; the 

 tuberculatum was remarkably uniform on both sides. In a very young 



