464 



PELMATOZOA. 



plate and deltoids. This family includes El<zacrinus (with an anal plate) ; 

 and Schizoblastus (fig. 332, c and d), Cryptoblastus, and Acentotremites 

 (without an anal plate). 



Family 4. Gra?iatoblastid<z. — Calyx globular or ovoidal, with a flattened 

 or concave base and linear ambulacra. Spiracles five, piercing the del- 

 toids ; or ten, grooving their lateral edges. This family includes the 

 genera Granatocri?ms and Heteroblastus. 



Family 5. Codasteridcs. — Base usually well developed and sometimes 

 very long. Some or all of the hydrospire-slits pierce the calyx-plates on 

 the sides of the radial sinus, restricted portions of which may remain 

 open as the spiracles. This family includes the genera Codaster (fig. 

 331, a), Phcenoschisma, Orophocrinns (fig. 331, B and c), and Crypto- 

 schisma. 



Order II. Irregulares. 



Family 6. Astrocrinidce. — This family includes certain singular un- 

 stalked and unsymmetrical Blastoids, in which one ambulacrum and one 

 radial are different from the rest. In Astrocrinus and Eleutherocrimis 

 the basals are unsymmetrical, and the azygos radial is small and without 

 definite limbs, its ambulacrum being short, wide, and horizontal. On the 

 other hand, in Peiitephyllum the basals are symmetrical, and the odd 

 ambulacrum is linear. 



LITERATURE OF ECHINODERMATA. 

 General. 



"Ueberden Bau der Echinodermen." ' Abhandlungen der Berlin 



Akad.' 1853. Joh. Miiller. 

 " Morphologische Studien an Echinodermen." H. Ludwig. Leipzig, 



1877-82. 

 " Histoire naturelle des Zoophytes Echinodermes." Dujardin and 



Hupe. Paris, 1862. 

 " Monographic d'Echinodermes vivants et fossiles." Louis Agassiz. 



1838-41. 

 " Handbuch der Palseontologie," Abth. I., Lief. 3. Zittel. 1879. 

 " Beitrage zur Histologic der Echinodermen," I. -IV. Hamann. 



1884-89. 

 " Die Stamme des Thierreichs." Bd. I. Neumayr. 

 " Bronn's Klassen und Ordnungen des Thierreichs " (Echinoderms). 



2d Ed. 1889. Ludwig. 

 " Notes on Echinoderm Morphology," I. -XI. ' Quart. Journ. Micro. 



Sci.' 1878-87. P. H. Carpenter. 



ECHINOIDEA. 



10. " Catalogue raisonne des families, des genres, et des especes de la 



classe des Echinodermes." Louis Agassiz and Desor. 1847. 



11. "Revision of the Echini." Alexander Agassiz. 'Memoirs of the 



Museum of Comparative Zoology at Harvard,' vol. iii. 1872-74. 



12. "Monograph of the British Fossil Echinodermata." Thomas 



Wright. ' Palseontographical Society.' 



13. " Etudes sur les Echinoidees." Svenska Vetensk. Handl' Bd. xi. 



1874. Loven. 



