Beginners' zoology . Fig. 244. — Lung Fish of Australia{Ceratodus mioleptis).. Fig. 242. — TCRPEDO. Elec-trical organs at right andleft of brain. Fig. 246. —Seaweed Fish, x^{Phyllopteryx eques). Remarkable Fish. Special Reports. (Encyclopedia, texts, dictionary.) 124 GENERAL CLASSIFICATION 125 RECOGNITION GROUP CHARACTERS The commoner members of the several branches may be recog-nized by the following characters : — 1. The Protozoans are the only one-celled animals. 2. The Sponges are the only animals having pores all over thebody for the inflow of water. 3. The Polyps are the only many-celled
Beginners' zoology . Fig. 244. — Lung Fish of Australia{Ceratodus mioleptis).. Fig. 242. — TCRPEDO. Elec-trical organs at right andleft of brain. Fig. 246. —Seaweed Fish, x^{Phyllopteryx eques). Remarkable Fish. Special Reports. (Encyclopedia, texts, dictionary.) 124 GENERAL CLASSIFICATION 125 RECOGNITION GROUP CHARACTERS The commoner members of the several branches may be recog-nized by the following characters : — 1. The Protozoans are the only one-celled animals. 2. The Sponges are the only animals having pores all over thebody for the inflow of water. 3. The Polyps are the only many-celled animals having a singleopening into the body, serving for both mouth and vent. Theyare radiate in structure, and usually possess tentacles. 4. The Echinoderms are marine animals of more or less radiateappearance, having a food tube in the body separate from thebody wall. The following groups are plainly bilateral: that is, dorsal andventral surfaces, front and hind ends are different. 5. The Vermes have usually a segmented body but lack jointedlegs. 6. The Arthropods
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1921
