BRYOZOA OF WOODS HOLE REGION. 24 1 



Lepralia americana Verrill. [PI. xxv, fig. 55, 55a.] 



Verrill 1875a, p. 415, name only, with pi. vn. fig. 4 (fig. 5 is L. pallasiana instead of americana), 

 Verrill 1875b, p. 42. name only, with distribution; 1879c. 

 Davenport 1891, p. 47 (L. pallasiana). 



2^arium encrusting on shells, stones, etc., forming rather rough whitish to reddish colonies, often 

 everal cells in thickness. Zooecia large, but averaging smaller than L. pallasiana, roughly quadrangular 

 or hexagonal, slightly convex and rising, often suddenl)-, to a more or less prominent umbo behind the 

 orifice; surface in young specimens always rather coarsely cancellated with large pores, very roughly 

 ribbed (sometimes radiatelyj in older stages of calcification; a raised border often separates tlie cells 

 in young colonies, but this is frequently overgro\\ii later by the thickening of the crust; orifice usually 

 a little quadrangular, slightly longer than broad, but sometimes nearly rounded, a denticle on either 

 side of the orifice near the posterior end, the aperture not widened behind the denticles, peristome 

 thin, slightly raised, often forming a sort of projecting lip on either side of the orifice. Goecia large, 

 subglobular, occasionally partly immersed, with a few verj' large, irregular pores on the upper surface. 

 A rounded avicularium is often present below the aperture at the top of the umbo. 



This species differs from pallasiana in the form of the zooecial aperture, in the possession of ovicells, 

 in the occasional possession of a raised border separating the cells, and in tlie more radiately ribbed 

 character of the calcification. 



Verrill very evidently confused this species with pallasiana. He gives no verbal description, but 

 his figure 4 (see above) issufficient for identification. His figure 5, labeled "the same without ootheca," 

 is L. pallasiana, however. 



Under the circumstances, it is manifestly impossible to quote Verrill in regard to the range of the 

 species, as in his earlier papers he placed everytliing in " ?L. pallasiana," and later called them all 

 americana. In this region the species is well distributed, being rather common in Vineyard Sound, 

 Muskeget Channel and Great Round Shoal, not common in Buzzards Bay, scarce at Crab Ledge, and 

 found occasionally on piles at Woods Hole and Nantucket. I have also seen specimens from Nantucket 

 Shoals and Long Island Sound. In general, it occurs in deeper water than pallasiana, but occasionally 

 they are found together. 



Lepralia pertusa (Esper). [PI. xxvi, fig. 56, 56a, 56b, 56c.] 



Esper 1791-1797, p. 149 {Cellepora pertusa). 



Dawson 1859. p. 256. 



Verrill 1879b, p. 414 {Escharetla perlusa}). 



Verrill 1S70, p. 193 {Escharina porosa, n. sp.). 



Hincks 1S92, p. 154. 



Whiteaves 1901. p. 101. 



Cornish 1907. p. 77. 



Zoarium encrusting stones and shells, and occasionally algae, forming colonics often of considerable 

 extent, of various shades of red or when young, silvery white. Zooecia ovate or more or less oblong, 

 rhomboid or hexagonal, regularly convex, separated by raised lines, surface smooth and glossy when 

 young, often considerably roughened when fully calcified, ptmctured with numerous rounded pores, 

 sometimes rising to a rough umbonate process behind the orifice; orifice rounded, a pair of lateral denti- 

 cles, behind which the oral margin is curved but without a distinct sinus, peristome slightly raised and 

 thickened, smooth. Ooecium large, prominent, subglobular. somewhat flattened above, punctured, 

 smooth, or the upper surface roughened and a smooth border around the base; in specimens from deeper 

 water tlie whole ovicell is usually roughened when fully calcified and an umbonate process occasionally 

 rises from the top. Avicularia rare, but occasionally a small oval one is seen at one side of the orifice 

 with the mandible turned somewhat obliquely either toward or away from the orifice. 



Very material differences exist in the size of the zooecia, but otherwise the variations are almost 

 entirely due to the amount of calcification. I have not observed in our specimens the large avicularia 

 figured by Hincks (1880, pi. xtm, fig. 4) but a specimen from Cashes Ledge given me by Prof. 



