VERMES 



•3' 



1 



FlG. 120. Ciistatella mucedo. Siato- 

 blasts; a, from flattened surface; 6, from 

 edge; magnified. (After Allman, from 

 i lau i am i Sei [gv\ i< k' I'ext-book.) 



there are no special-sense organs. 

 The Bryozoa are mostly hermaph- 

 roditic, with distinct ovaries and 

 testes, and the germ-cells arc set 

 free into the body-cavity ( Fig. 

 119). 



Reproduction is both sexual 

 and asexual. In the former case 

 a partially ciliated larva is gener- 

 ally produced, such as Cypho- 

 nautes, which is like the larvae 



of many other worms. Asexual reproduction is 

 by means of budding, which gives rise to the 

 colonies, and also, in many fresh-water Bryozoa, 

 by means of structures called statoblasts (Fig. 

 120). These generally develop towards the latter 

 part of summer and appear as a group of cells 

 within the body-cavity, which become inclosed in 

 a firm chitinous membrane or shell, biconvex in 

 shape, and sometimes having projecting spines or 

 hooks. The animal generally dies during the 

 winter, and in the spring the contents of the 

 statoblast develops into a new bryozoon. These 

 structures then are of the nature of internal 

 buds, and recall the gemmulae of the fresh-water 

 sponges. 



CLASS II. PHORONIDEA 



The Phoronidea (Gr. Qopoovfc, name of a king) 

 are represented by a single genus, Phoronis (Fig. 

 121). They are hermaphroditic, marine worms, 

 living in the sand. They have an elongated, 

 cylindrical body, ten centimeters or more in 

 length, inclosed in a membranous tube within 

 which they can withdraw, and bear a crown of 

 ciliated tentacles on a horseshoe-shaped lopho- 

 Fig. 121. Phoroms phore. In their adult structure they closely 

 size. a < After Parker resemD l e the Ectoprocta among the Bryozoa. 

 and Hasweii.) Reproduction is exclusively sexual so far as we 



