8 Henry Woodward — On a New Devonian Starfish. 



tliat peculiar many-rayed family, tlie Solasteri^, or " sun-stars," of 

 which only three species, belonging to as many distinct genera, 

 — namely, Helianthnster, Lepidaster, and Trochitaster — have hitherto 

 heen described from the Palaeozoic rocks, whilst a starfish which 

 has been referred by the late Prof. Edward Forbes to the living 

 genus Solaster, occurs as early as the Great Oolite.^ 



Of the other Devonian genera, Aspidosoma, Asterias, and Palaaster 

 belong to the family of Asteri^, whilst Protaster is referred to the 



OPHIURIDiE. 



Although, as a rule, the number five is dominant among the 

 Echinodermata, and regulates the forms and organs of the starfishes, 

 yet we find numerical variation occurring more frequently in this 

 order than among the Ophiurse or the Sea-Urchins. 



The number of arms is not of specific value, although in several 

 instances it may be of generic significance. In Luidia and Solaster, 

 says Prof. Edward Forbes, it is of least importance. 



The purple sun-star, Solaster endeca, has from nine to eleven rays ; 

 the common sun-star, Solaster papposa, has generally from twelve to 

 thirteen rays, sometimes as many as fifteen; whilst the Solaster 

 heliantJioides, a fine specimen of which I possess, from the western 

 shores of South America,* has no fewer than thirty -four arms ! 



The Solaster Moretonis, from the Great Oolite, has thirty-three 

 arms ; Helianthaster Khenanus, from the Devonian slates of Ardoise, 

 has sixteen arms ; Lepidaster Grayi, from the Wenlock Limestone, 

 Dudley, has thirteen arms ; Trochitaster plumiformis, from the same 

 formation and locality, has ten rays : both the examples of Mr. 

 Champemowne's Starfish have eleven arms. 



Helianthaster JiUciformis, H. "Woodw., Devonian, Harbertonford, 

 South Devon. (Twice the natural size.) 



' Solaster Moretonis, Forbes, Mem. Geol. Surv., Decade 5, t. 1. 

 * Fide Forbes, possibly from Australia ? 



