EEPOET ON THE ASTEEOIDEA. J XXX1U 



Family VI. Pentacerotid^e (Gray), emend. Perrier, 1884. 



Phanerozonate Asterids with unequally developed marginal plates, the superior series 

 being frequently masked or hidden in membrane. Abactinal skeleton reticulate. Plates 

 with large isolated tubercles or spinelets, or granulose-, or covered with membrane. Actinal 

 interradial areas with large pavement-like plates, which bear unequal-sized granules. 



Genus 1. Pentaceros, Linck. 



.Genus 2. Nidorellia, Gray. 



Genus 3. Arrvphiaster, Verrill. 



Genus 4. Pentaceropsis, n. gen. 



Genus 5. Culcita, Agassiz. 



Genus 6. Asterodiscus, Gray. 



Genus 7. Choriaster, Liitken. 



Genus 8. Paulia, Gray. 



For a Synopsis of the Genera included in the Family Pentacerotidee, see p. 343. 



Family VII. Gymnasteriid^e, Perrier, 1884. 



Phanerozonate Asterids with unequally developed marginal plates. Abactinal skeleton 

 tessellate, the plates being often irregular and only partially contingent. The whole test 

 covered with membrane, which may be simple, or granulose, or beset with spinelets. 

 Actinal interradial areas with large regular plates, often in isolated serial arrangement. 



Genus 1. Asteropsis, Mtiller and Troschel. 



Genus 2. Dermasterias, Perrier. 



Genus 3. Gymnasteria, Gray. 



Genus 4. Tylaster, Danielssen and Koren. 



Genus -5. Porania, Gray. 



Genus 6, Marginaster, Perrier. 



Genus 7. Rhegaster, Sladen. 



Genus 8. Poraniomorpha, Danielssen and Keren. 



Genus 9. Lasiaster, n. gen. 



For a Synopsis of the Genera included in the Family Gymnasteriidse, see p. 355. 



Family VIII. Asterinid^e (Gray, 1840), emend. Perrier, 1875. 



Phanerozonate Asterids with small marginal plates, in some forms inconspicuous and 

 with their axes convergent. Abactinal skeleton composed of imbricating and usually 



(ZOOL. CHALL. EXP. — PART LI. — 1888.) 6 



