BRYOZOA OF WOODS HOLE REGION. 215 



KEY TO FAMILIES. 



1. Zoarium erect, articulated, with horny joints, attached by long tubular radical processes. . .Crisiidae. 

 Zoarium entirely or partially encrusting (sometimes only the small basal portion for attachment), not 



jointed, solidly attached, without radical fibers 2. 



2. Zoarium discoid, simple and entirely or partially adnate, zooecia tubular, erect or nearly so, radiating 



in linear series from a free central area, intermediate space cancellated Lichenoporidae. 



Zoarium flabellate, lobate or branched, entirely adnate or rising from an encrusting base, zooecia 

 tubular, in contiguous series or in single lines Tubuliporidse. 



Family CRISIID^ d'Orbigny, 1853. 



The jointed zoarium, the erect, bushlike habit of growth, the attachment by means of jointed 

 tubular fibers, and the swollen, pear-shaped ooecium, which is merely an expanded cell, easily serve to 

 distinguish this family at a glance from any other. There is only one genus. 



Genus CRISIA Lamouroux (pars), 1812. 



KEY TO SPECIES. 



Zoarium bushy, spreading, tips of branches curled inward, ooecium with a well developed tubular 

 ooeciostome, the aperture of which is somewhat elongate transversely and inflexed on the front 

 border eburnea. 



Zoarium more erect, somewhat flabellate, the branches not curved inward; ooeciostome shorter than 

 in the preceding and conspicuously elongated transversely, twice as long as wide cribraria. 



Zoarium much as in eburnea; ooeciostome not well developed, very short, the aperture round .denticu lata. 



Crisia eburnea (Linne). [PI. xvm, fig. 6, 6a, and 6b.] 



Linne 1766-1768, p. 1316 (Scrtularia eburnea). 

 Verrill and Smith 1874, p. 707. 

 Verrill 18790, p. 28. 

 Cornish 1907, p. 78. 



Zoarium forming dense, bushy tufts, usually attached by a single stem, the base of which does not 

 in most cases develop many rootlets; height y to ^ inch, the branches characteristically curved 

 inward. Internodes short, somewhat flattened, in most cases with an odd number of zooecia, 5 and 7 

 being the dominant numbers. Joints yellow, colorless near the growing points, sometimes dark brown 

 in old parts of the colony. Zooecia almost entirely connate, the free upper portion bearing the aperture 

 bent forward nearly at a right angle to the stem, a pointed process sometimes on the outer angle of the 

 aperture. Ovicell large, curved inward, usually replacing the second, less often the third zooecium of 

 an internode; ooeciostome conspicuous, elongated transversely (i% times as long as wide), the front 

 margin somewhat inflexed, borne on a very distinct tube which narrows toward the summit. 



An abundant species, growing in all depths from low water to the deepest water of the region. 

 Found on piles, attached to hydroid and other stems, on stones and shells, in fact on anything which 

 will give it a foothold. More abundant in Vineyard Sound and outside waters, but plentiful in many 

 parts of Buzzards Bay. 



Crisia cribraria Stimpson. [PI. xvm, fig. 7, 73, and 7b.] 



Stimpson 1853, p. 18. 



Harmer 1891, p. 135 (? = C. ramosa Harmer). 



Verrill 18790, p. 28 (C. eburnea var. cribraria). 



Jelly 1889, p. 74 ( = C. denticu lot a). 



Whitcaves 1901, p. no (C. ebiirneavar. cribraria). 



Stimpson's original description of this species is as follows: " Polydom thickly branched, with the 

 cells so crowded as to form 2 or 3 longitudinal rows, in which they are usually opposite. The back of the 



