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MOLLUSCA. 
DIVISION III.—ARTICULATA. 
Class V. Annelides Class VIII. Myriapoda 
VI. Crustacea IX. Insecta 
VII. Archnides 
DIVISION IV.—RADIATA. 
Class X. Echinodermata Class XIII. Polypi 
XI. Entozoa XIV. Infusoria 
XII. Acalepha 
The arrangement adopted is that of Lamarck, but reversed in 
the order. 
ORDER I— HETEROPODA. 
Head distinct, with two eyes, but destitute of arms arranged 
around the head ; body free, elongated, fitted for swimming hori¬ 
zontally ; no foot under the abdomen or throat for walking ; one 
or more fins, without any regular order, and not arranged in 
pairs as in fishes. 
Genus 1.—PHYLLIROE.— Lamarck. 
Generic Character. —Head distinct, with two tentaculi, two 
eyes, and a proboscis ; body oblong, greatly compressed, almost 
lamelliform ; tail forming a single fin ; branchiae situated inter¬ 
nally, and resembling granulated filaments. 
Genus 2. —P T E RO T RA CHE A.— Lamarck. 
Generic Character. —Head distinct, with horny jaws, two 
eyes, but no tentacula; branchiae penniform, protruding external¬ 
ly, and placed along with the heart under the abdomen, contigu¬ 
ous to the tail; body free, oblong, gelatinous, pellucid, with a 
terminal tail, having one or more fins. 
Genus 3.—CARINARIA.— Lamarck. 
Generic Character. —Head distinct, provided with two ten¬ 
tacula, a contractile elongated mouth, and two eyes; heart and 
branchiae united into a single mass, projecting from the abdo¬ 
men, contiguous to the tail, and enveloped in a shell; body 
