34 NATURAL HISTORY BULLETIN 



A number of the genera do not have free-swimming larvae,* 

 but are known to carry their eggs and larvae attached about the 

 mouth, or else in a marsupial pouch (gonocodium) until they 

 become true starfishes, large enough to care for themselves. This 

 habit is usually associated with the lack of pedicellarige. It is 

 conducive to the formation of local varieties. The order may 

 be naturally divided into two suborders : 



Suborder I — Avelata Ver., op. cit., 1913 ; 1914a, p. 204.* 



This includes the more typical forms in which there is no 

 dorsal, tent-like marsupial chamber for the protection of the eggs 

 and young. The spines are either all free, or partially or wholly 

 webbed together into groups, as in Solasteridce, in which the 

 groups of adambulacral spines form transverse combs complete- 

 ly webbed together, and the dorsal spinules are partially so. 

 It includes the following families represented in this collection : 

 Echinasteridce; Solasteridce; KoretJirasteridte, deep sea; Aster- 

 inidce; Poramidw. Also, the following extralimital families, be- 

 sides other smaller groups: Acanthasteridce; Mithrodidm; Py- 

 thonasteridce, deep sea; Myxasteridce, deep sea. 



II — Suborder Velata Perrier (as an order). 



This group includes only the family Pter aster idee. It is re- 

 markable for having most of the spines webbed together in clus- 

 ters and for the remarkable development of a superdorsal mem- 

 brane, more or less completely uniting the paxill^ together, and 

 usually forming a dorsal marsupial pouch or gonocodium in 

 which the eggs and young are carried. 



Suborder Avelata Verrill (See above). 



Family Echinasterid^ Verrill (restricted). 



EcMnasteridce Verrill (pars), Trans. Conn. Acad. Sci., i, p. 343, 1867. Per- 

 rier (pars), Eevis. Stell., Arch. ZooL, iv, pp. 299, 358, 1875. 



Echinmterince Viguier, Arch. Zool. Exper. ©t Gen., vii, p. 123, 1878 (struc- 

 ture. ) 



Ecliinasteridw Sladen (pars), Yoj. ChalL, xxx, p. 535, 1889. Bell, Catal. 

 Echinod., pp. 23, 95, 1890. Perrier, Etoiles de Mer, Nouv. Arch. 

 Mus. Nat. Hist., vi, p. 164, 1884; Exp. Trav. et Talism., pp. 28, 141,. 



* This is the case with the genera Hen/ricia, Ptera^ter, Hymenaster, and 

 others. 



* There once misspelled as Alvelata. 



