482 The Animal Kingdom 



shelled cephalopods that dwelled throughout the oceans during the Silu- 

 rian to Cretaceous periods. The shells of these fossil forms are abund- 

 ant in marine deposits. 



SOME MINOR EUCOELOMATE PHYLA 



The phyla Bryozoa, Brachiopoda, and Phoronida all possess a 

 lophophore, a trochophore larva, and a true coelom. It is possible that 

 these phyla arose from a common ancestor along with the annelids, 

 molluscs, and arthropods. 



The Phylum Bryozoa. — These animals (Fig. 159,C) usually live 

 in colonies which are matlike in appearance ; hence the name bryosoan 

 meaning moss animals. They grow on pilings, rocks, shells, and even 

 on other animals. The majority are marine, though a few fresh- water 

 forms are known and may be locally abundant. 



TENTACLE 

 LOPHOPHOBE 

 GANGLION 

 ANUS 



FUNICULUS 

 TESTIS 



Fig. 159. — Some minor eucoelomates. A, Phoronis, a phoronid; B, a statoblast 

 of the fresh-water bryozoan, Pectinatella; C, Bugula, a bryozoan; D, Lingula, a 

 brachiopod. 



The individual, known as a sooid, possesses a horseshoe-shaped 

 lophophore which bears a row of slender ciliated tentacles. There is a 

 well-developed coelom and a complete digestive tract with the mouth 

 inside the lophophore and the anus opening outside. Excretory organs 

 and a vascular system are absent. Most species are hermaphroditic. 



The anatomy of this group may be illustrated by the marine colonial 

 form, Bugula, which forms mats of dark-colored tufts attached to various 

 objects. These tufts are some 2 to 3 inches long and consist of many 



