24 VERRILL 



dorsal and lateral ossicles, or stand singly, or they may occur only in 

 special areas. Rarely they are branched. 



Most shallow-water starfishes that have been studied in this respect 

 have a free-swimming, bilateral larval form, known as a brachiolaria ; 

 yet a considerable number carry their eggs and young till they 

 develop the starfish form, as explained above. These have an abbre- 

 viated metamorphosis. The two methods may occur in different 

 genera of the same family (e. g., Asteriidce). 



The embryology of the deep-sea species is unknown in most cases, 

 and may be diverse, or even more abbreviated. 



CLASSIFICATION OF ASTERIOIDEA. 



In this report I have adopted the division of the class into three 

 large orders, viz. : 



I. FORCIPULOSA or FORCIPULATA. 

 II. SPINULOSA. 

 III. PHANEROZONA. 



The last has two suborders, considered orders by some recent 

 writers, viz. : 



I. VALVULOSA or VALVATA. 

 II. PAXILLOSA. 



Order FORCIPULOSA Verrill, or FORCIPULATA Perrier. 



Stellerida forcipulata PERRIER, Mem. Etoiles de Mer, pp. 166, 188, 1876. 



Forcipulata PERRIER, Exped. Sci. Trav. et Talisman, p. 27, 1894. 



Asteries Ambulacraires VIGUIER, Squellette des Stellerides, Arch. Zool. Exper., 



vii, p. 93, 1878. 



Cryptozonia (pars) SLADEN, Voy. Chall., xxx, pp. xxxiv, 397, 1889. 

 Adetopneusia (pars) and Leptostroteria (pars) SLADEN, op. cit, p. xxxiv. 



The form is always stellate, often with long rays, commonly five, 

 but often multiple. Ambulacral plates, except the orals, are usually 

 short and closely crowded (leptostroterial) , but not in Brisingidae. 

 The proximal pair is elongated and, except in Pedicellaster and a 

 few others, forms the inner end of the jaw. Ambulacral feet are 

 generally arranged in four rows, but in two rows in Pedicellas- 

 teridae, Brisingidae, and Zoroasteridae. 



In some large species of Pisaster they may form six or more rows 

 by crowding, especially subproximally. They are always terminated 

 by suckers. 



