550 
TUNICATA. 
Section IV.— Crinoid^e. 
Genus P E NT A GRIN US.— Thompson. 
Generic Character.-^-F elvis consisting of five plates, support¬ 
ing five costals; column not enlarging at the summit; fingers 
formed of a single series of joints; having a pentagonal column, 
the articulating surface of the columnar joints petal-shaped. 
The Pentacrinus Europeus inhabits the Cove of Cork. 
CLASS XL—TUNICATA. 
Gelatinous or coriaceous biferous animals; with double coats 
isolated, placed in groups, or adhering together in a common 
mass. 
In assigning a place to this class, we have followed the ar¬ 
rangement of invertebrate animals adopted by Lamarck. 
ORDER I_ASCIDIARIA. 
Animals disunited, either isolated or placed in groups, with¬ 
out any internal communication ; and not connected in a com¬ 
mon mass. 
The genera of this order are four, viz.: — 
Genus 1. —M A MM ARIA.— Lamarck. 
Generic Character .—With a free, naked, subglobular, or oval 
body, terminated at the summit by a single opening; destitute 
of tentacula at the orifice: 2. Bipapillaria; 3. Ascidia; and 
4. Salpa. 
ORDER II.—BOTRYLLARIA. 
Agglomerated animals, always united, and combined in a com¬ 
mon mass. 
Its genera are, 1. Pyrasoma; 2. Botryllus; 3. Polycyclus; 
4. Polycinum; 5. Diagoma; G. Distomus; 7. Sigillina; 8. Sy- 
noicum ; 9. Eucoelium ; and \ 
