240 BULLETIN OF THE BUREAU OF FISHERIES. 



4. A small avicularium situated at the apex of a prominence immediately below the orifice in the 



median line and often included within the sinus-like fold of the secondary orifice Porella. 



Oral avicularium absent, or, if present, larger and not mounted on a definite rostrum, a prominent 

 tooth or shelf-like projection on the posterior border of the primarj' orifice (occasionally absent), 



Smittia. 

 Genus LEPRALIA Johnston (pars), 1849. 



Zoarium in our species encrusting, or rarely rising free for a few millimeters; zooecial orifice without 

 mucro or avicularium, peristome raised or not; lateral margin of the orifice with a small denticle on 

 each side toward the posterior border, no sinus, but sometimes the posterior border rounded between 

 the denticles so as to give at first glance the appearance of a very broad sinus. 



KEY TO SPECIES. 



1. Orifice large, elongate, distinctly widened near its posterior end; ooecia and avicularia wanting, 



pallasiana. 



Orifice smaller, more rounded, or if elongate, not widened posteriorly, ooecia and avicularia present, 



at least occasionally 2 . 



2. Oral margin anteriorly with its inner edge finely serrate, lateral denticle large, bifid; avicularia 



abundant, usually of two sizes; ooecium broader than long, with a transverse membranous area 



above orifice serrata. 



Without such characters 3. 



3. Zooecial and ooecial pores small and numerous; zooecial orifice rounded, the transverse diameter 



often slightly the longer; the projecting marginal denticles give the rounded posterior border the 



appearance of a very broad sinus pertusa. 



Zooecial and ooecial pores few and large ; zooecial orifice more quadrangular, usually somewhat widest 

 posteriorly americana. 



Lepralia pallasiana (Moll). [PI. xxv, fig. 54, pi. xxx, fig. 89.] 



Mull 1803. p. 57 {Eschara pallasiana). 



Leidy 1855, p. 9 {Escharina pediostoina). 



Verrill and Smith 1874. p. 713 (? Lepralia pallasiana). 



Verrill 18753 (pi. vn. fig. 5 under L. americana, n. sp.). 



Cornish 1907. p. 77. 



Zoarium encrusting shells, stones, submerged wood, and algae, the colonies circular when the nature 

 of the substratum will permit, sometimes as much as 2 inches in diameter. Zooecia large, often quad- 

 rangular or roughly hexagonal, but varying greatly in this respect; somewhat convex and rising toward 

 the orifice, punctiu-ed with rather large pores, in young stages smooth and glossy, when older often 

 rough, with thick ridges between the pores; orifice large, considerably longer than wide, widened 

 rather suddenly near the posterior end, with a small denticle on either side just in front of the expanded 

 portion; peristome thin, smooth, and only slightly raised in our specimens. Ovicells are unknown in 

 this species and avicularia are apparently wanting in specimens from this region. An umbonate process 

 is sometimes present below the orifice. 



Well distributed throughout the region from low water to 8 fatlioms or deeper, best developed in 

 the shallower waters. Woods Hole, New Bedford, and Nantucket harbors, on piles, West Falmouth 

 harbor in shallow water, Cedar Tree Neck at low tide. Buzzards Bay, Vineyard Sound and Great 

 Round Shoal. 



The species has been recorded from Canadian waters at Canso only (Cornish). Leidy figured it 

 as Escharina pediostoma from Beesley's Point, N. J. Verrill had it among his material, for one of his 

 figures (fig. 5) of L. americana is unquestionably pallasiana. I have specimens from Long Island Sound 

 and from the nortli shore of Cape Cod, near Sandwich. 



