xl THE VOYAGE OF H.M.S. CHALLENGER. 



Remarks. — The genus Coronaster is referred by M. Perrier to the Brisingidse, but I 

 am unable to recognise in the description any characters to warrant that classification. I 

 have therefore ventured to place it with doubt in this family. The description of Astrella 

 is so very brief that I am unable to form any definite opinion as to the family to which it 

 shoidd be referred. Its position in the Asteriidee can therefore only be considered pro- 

 visional, until a complete description is published. The form described appears to be 

 immature. Some of the characters mentioned by M. Perrier suggest at first the thought 

 that the affinities of Astrella might be with the Archasteridse, but the presence of the 

 transverse ossicles between the adambulacral and marginal plates would seem to negative 

 that view entirely. 



For a Synopsis of the Genera included in the Family Asteriidse, see p. 560. 



Family X. Brisingid.e, Sars, 1875. 



Cryptozonate Asterids with numerous very elongate rays readily detachable from 

 the disk. Marginal plates in part aborted altogether, elsewhere represented only by 

 microscopic rudiments. Abactinal skeleton aborted or present only on the ovarial regions. 

 Actinal intermediate plates altogether absent. Long lateral spinelets. Spinelets in sheaths 

 crowded with pedicellarias. No interbrachial septa. 



Genus 1. Labidiastcr, Liitken. 



Genus 2. Odinia, Perrier. 



Genus 3. Brisinga, Asbjprnsen. 



Genus 4. Freyella, Perrier. 



Genus 5. Colpaster, n. gen. 



? Genus 6. Brisingaster, de Loriol. 



? Genus 7. Hymenodiscus, Perrier. 



? Genus 8. Gymnobrisinga, Studer. 



Remarks. — I feel much doubt as to the generic validity of the three last-mentioned 

 genera. 1 have therefore placed a query before each of them, pending the establishment 

 of their independence as genera distinct from Brisinga. 



For a Synopsis of the Genera included in the Family Brisingidse, see p. 589. 



The following Synopsis of the principal divisions of the Sub-class will bring the classifi- 

 cation of the group into a compact form ; it will" also be useful in showing negative and 

 antithetical characters not included in the foreo-oino; diagnoses : — 



o 



Synopsis of the Orders and Families of the Sub-class EUASTEROIDEA. 



I. Marginal plates large and highly developed in the adult. Papulae restricted 

 to the abactinal area, circumscribed by the supero-rnarginal plates. 

 Ambulacral plates well spaced and usually broad. Actinostornial ring 



