46 INVERTEBRATE ANIMALS. 



Sub-Class CRINOIDA. 

 Hpivos, a lily; sI'^jos, form. 

 Body of the animal, during the whole or a portion of its 

 existence, attached to the sea-bottom by a jointed and 

 flexible stalk. 



Group 133.— Orders CYSTOIDEA, BLASTOIDEA, and 

 CRINOIDEA in part. The Cystoidea, earliest of the 

 Echinoderms, attained their maximum in the Lower 

 Silurian. They were closely followed by the Blastoidea, 

 or Pentremites, and the Crinoidea, or Stone-Lilies : the 

 latter alone survived, though in diminished numbers, 

 the Palaeozoic age. Estimated number of species, 



140. M. DUJARDIN. 



Group 134.— Family PENTACRINID^ (D'Orbigny). The 

 beautiful Pentacrinus Midleri is one of the few living 

 forms which very closely connect the animal life of the 

 present age with that of ages immeasurably remote. 

 Living in the deeper waters of the Caribbean Sea, it 

 has seldom been brought to light, and was long 

 - regarded as a solitary relic of the vast Crinoid popula- 

 tion of the ancient oceans. Deep-sea dredging has 

 recently afforded examples of allied forms. Pentacrinus 

 Wyville - Thomsoni was taken at a depth of 1,095 

 fathoms, E. Atlantic, and Bathycrinus gracilis at 2,435 

 fathoms. Estimated number of species : recent, 6 ; 

 fossil, 6. Lias. 



The collection is fortunate in possessing one fine 

 specimen of P. Alidleri and two of P. Wyville- 

 Thomsoni. Whilst inspecting them Dr. Car- 

 penter, who described and named the latter 

 species, remarked to the writer that, in conse- 

 quence of a structural peculiarity, the stem of 



