Zöology; a textbook for colleges and universities . ECHINODERMA TA 22$ which has had the temerity to attack the large lobster has been seen thus ensnared, and quiteunable to move. It might be supposed that this modeof defense would be fatal to the sea cucumber, butthat animal merely goes into retirement for a time, andregenerates the lost parts. The wormlike species (Synapta) behave posterior part of the body is amputated, while thehead with its feelers buries itself in the sand or Echinodermata, whatever their origin, have them-selves given rise to no oth
Zöology; a textbook for colleges and universities . ECHINODERMA TA 22$ which has had the temerity to attack the large lobster has been seen thus ensnared, and quiteunable to move. It might be supposed that this modeof defense would be fatal to the sea cucumber, butthat animal merely goes into retirement for a time, andregenerates the lost parts. The wormlike species (Synapta) behave posterior part of the body is amputated, while thehead with its feelers buries itself in the sand or Echinodermata, whatever their origin, have them-selves given rise to no other groups. They represent aseparate branch of the tree of life, as do the sponges andmollusks. CHAPTER THIRTY BRYOZOA Characters i. THE Bryozoa (the term meaning moss animals) ofBryozoa n are small aquatic creatures, mostly marine, nearly. From Animate Creation FIG. 54. Bryozoans, Plumatella, from fresh water. The upper figure greatly enlarged. always living in colonies or zoaria, often looking verymuch like seaweeds or corals. Each separate individ-ual (zooid) is placed in a membranous or calcareous(limy) sac, called the zooecium. They differ entirelyfrom coral animals in possessing an alimentary canalwith two openings, and a well-developed nervous system,distinct body cavity, etc. The mouth is surrounded bydelicate respiratory tentacles. The colonies are formedby gemmation or budding, but the animals have sexualorgans, being usually hermaphroditic. There is noheart or true blood system. The Bryozoa are of great antiquity, and are abun- 226 BRYOZOA 227 dantly preserved as fossils. Like the much more primi- Antiquity oftive sponges, they represent an isolated type, which hasproduced a great number of genera and species, withoutshowing much real progress. BRACHIOPODA I. The nearest relatives of the Bryozoa are the so- st
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
