THE BRYOZOA — BASSLER. 

 Subclass ECTOPROCTA. 



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Almost all of the known bryozoa, both fossil and recent, belong to 

 the Ectoprocta (<?A-fo,s'=without, pro kfos= anus), characterized by 

 the position of the anus without the row of tentacles surrounding the 

 mouth. Here again two very unequal divisions have been instituted, 

 the Phylactolaemata with a horseshoe-shaped lophophore, repre- 

 sented by a few species, and the Gymnolaemata, with a circular 

 lophophore, comprising practically all the fossil forms and the great 



tentacles 



embryos 



Fig. 3. — Structure of the Entoprocta. 1-3, PediceUina cernua Pallas. Atlantic off Eng- 

 land. 1. Polypide borne on a flexuous stolon showing a spinose peduncle, X36. 2. 

 Several polypides in various stages of growth, X20. (After Hincks.) 3. An entiro 

 colony, X22, exhibiting three growing ends (a) ; zooids 1 and S are quite immature; 7 

 (tentacles retracted) is still young; 2 is seen in longitudinal section; g, generative 

 organ, and below it the ganglion ; m, mouth ; r, rectum ; s, stomach ; between g and r 

 are three embyros in the brood-pouch ; the tentacles are retracted ; in 5 and 6 the 

 tentacles are expanded ; in 6 two embryos are seen within the circle of the tentacles ; 

 to the left of them is the rectum, and to the right the mouth ; 3 is in the act of losing 

 its calyx, and has already developed the beginning of a new polypide-bud ; in 4 the 

 primary calyx has been lost, and the new calyx is clearly marked off from the stalk. 

 4. Loxosoma cirrifcrum Harmcr, an entoproctous bryozoan from the East Indies. A 

 female polypide magnified, showing the circle of tentacles with several embryos within 

 them and buds in various stages of development. (After Ilarmer.) 



majority of living species. Unlike the Entoprocta, the reproductive 

 organs are developed in the body cavity and have no ducts leading 

 into the vestibule, while specific excretory organs are absent. 



Superorder PHYLACTOLAEMATA. 



The bryozoa of this superorder have the tentacles arranged in a 

 horseshoe shape about the mouth, which is protected by an over- 

 hanging lip. They are fresh water in their habitat and have special 

 peculiarities which allow them to live under conditions where the 



