BRYOZOA OF WOODS HOLE REGION. 249 



americana. The orifice in the young cell is nearly round ; the lateral denticles are like those of a Lepralia 

 and the margin curves backward in an evenly rounded fashion on the posterior border. Hincks placed 

 the species in Lepralia. In Jelly's Catalogue it is placed under Smittia, for which I can see no verj- 

 good reason, and Norman and Whiteaves list it as a Porella, on account of the rostrum and avicularium. 

 Not uncommon at Crab Ledge and off Sankaty Head in 14 to 25 fathoms. Recorded by Verrill "off 

 Buzzards Bay, 25 fathoms; Nantucket Shoals, abundant; Bay of Fundy, etc." 



Porella proboscidea Hincks. [PI. xxvii, fig. 71, 71a, 71b, 71c, pi. xxxi, fig. loi.] 



Hincks 188S. p. 211. 



Verrill 18753. p. 414 (Eschara verrucosa), 1879b. p. 194, and 1879c, p. 30 {Porella -verrucosa Esper). 



Zoarium rising erect from an encrusting base, forming bilaminate folded frills, often of singular 

 beauty, rising to a height of one-half to one inch, growing on stems and occasionally on shells and pebbles, 

 white or light yellowish in color. Zooecia of moderate size, convex, with a row of areolae about the 

 margin and strong ribs running between these toward the center often to the base of tlie rostrum; a 

 raised border is present in the young cells but is soon obscured by calcification; in older cells the front 

 wall becomes exceedingly thick, covering the ribs, the raised margins, and even the rostrum, producing 

 a rather smooth, flat, continuous layer; the marginal areolae are usually distinct even in old cells, however. 

 Primary orifice rounded in front, straight posteriorly; peristome rising evenly, embracing the rostrum 

 and continuous with the ovicell, often rising high above both as calcification proceeds; the secondary 

 orifice thus produced is more or less pyriform witli the pointed end posterior. Avicularium small, 

 round, situated at the top of a strong rostrum which curves somewhat forward over the orifice, in a few 

 cases a pointed projection rising from the top of the rostrum just behind the avicularium. Ooecium 

 moderately large, subglobose, smooth and imperforate, prominent in the young state, completely 

 immersed when calcification is complete, continuous with the peristome in its formation. 



There is no doubt that this is the species which Verrill recorded as Eschara verrucosa (Esper) from 

 Cashes and Jeffreys Ledges, as I have seen specimens so marked in his collection. It is not Esper's 

 species, however, as that is the Umbonnla verrucosa (Esper), and I have compared both English and 

 Canadian specimens. 



Abundant at Crab Ledge, 14 to 20 fathoms. Great Round .Shoal, 8 fathoms; off Sankaty Head ESE., 

 23 fatlioms; off No Mans Land (Fish Hawk station 7784), 29 fathoms, Nantucket .Shoals. The finest 

 specimens I have seen were on the stems of the ascidian Boltenia, where, in one case, a colony several 

 inches in length completely encircled the stem and formed a complicated set of frills. 



Suborder CTENOSTOMATA Busk, 1852 



This suborder is characterized, among the marine cctoprocts, by the entire absence of calcification. 

 The walls may be strengthened by impregnation witli argillaceous matter, or they may be more or less 

 chitinous, or, not infrequently remain quite soft. Avicularia, vibracula, and ooecia are absent. The 

 zoarium may be stolonate or encrusting, and may rise in Uie form of phytoid branches or fleshy lobes. 



KEY TO FAMILIES. 



1. Zooecia immersed in a gelatinous crust, not stolonate 2- 



Stolonate, zooecia not immersed in a gelatinous la5'er 3. 



2. Crust armed with homy spines, zooecial orifice bilabiate, with a movable lip acting as an operculum, 



Flustrellidae. 

 Crust without spines, no labia present, orifice closed by mere invagination of tentacle sheath 



Alcyonidiidse. 



3. Zooecium with a flattened area, more membranous than the rest of the wall, occupying nearly all of 



the ventral side Triticellidae. 



Zooecium without flattened ventral area 4- 



