242 BULLETIN OF THE BUREAU OF FISHERIES. 



Verrill and labeled " Escharella Candida Stimpson" has these exactly as in Hincks figure. Verrill's 

 Escharina porosa is L. perttisa with the small avicularia at the side of the orifice, and it may possibly be 

 worthy of a varietal rank, but it seems to intergrade with the ordinary form entirely, and the avicularia 

 are but rarely developed. A comparison with British specimens of pertusa shows a close agreement in 

 the essential characters of the species. 



Occurs commonly throughout the Woods Hole region, dredged in 3 to 20 fathoms. Vineyard Sound, 

 Buzzards Bay, Great Round Shoal, Crab Ledge. The species is cosmopolitan, and on our coast occurs 

 from Florida to Labrador and Greenland. 



Lepralia serrata, new species. [PI. xxvi, fig. 57, 57a, 57b, 57c.] 



Zoarium encrusting, usually on stones and shells, occasionally on algae, at first smooth in subcircf.lar 

 colonies, later piling up into a rough crust of several layers of cells, occasionally rising free into irregular 

 frill-like projections a few millimeters in height. Zooecia roughly ovate or hexagonal, convex, becom- 

 ing very gibbous with age when distinct, but usually the cells unite as calcification proceeds and become 

 immersed in the common crust; surface rather smooth in the very young cells, vitreous and shining, 

 with a row of perforations around the margin, later the surface becomes very rough and the perforations 

 may or may not persist; orifice longer than broad, ovate, broader anteriorly, with a large bifid denticle on 

 either side posteriorly, dividing the orifice into a larger, anterior portion, the margin of which is finely 

 and evenly serrate, and a smaller posterior portion with a smooth border; the denticle has its points 

 widely divergent, the posterior point being the larger; four or five stout spines project forward from the 

 oral margin in the young cell, but these are deciduous and their bases are covered bj- the later calcifica- 

 tion; a secondary raised wall, often with a strong projecting mucro, rises high about the aperture, giving 

 it an entirely different appearance, but the primary orifice with its denticles and serrated inner margin 

 can be distinguished at the bottom. The ovicell is very striking and characteristic, very prominent, 

 smooth, nearly hemispherical, with a large, somewhat semilunate membranous area on the side next 

 the aperture, with a calcified area between this and the ooecial orifice. Avicularia immersed, or mounted 

 on a mamillate process, ovate to nearly spatulate in outline, occasionally wanting, but usually one to 

 several, very irregularly arranged, usually small but often large; the avicularian aperture, when the 

 mandibles are removed, often finely serrate like the oral margin. 



There isanenormousamountof variation in the extent and character of the calcification, in the shape 

 of the secondary orifice, and in the size and arrangement of the avicularia, but the characters of the 

 primary orifice and ovicell are very constant. Colonies growing on algae in Buzzards Bay (Phalarope 

 station 131) have very elongate oral spines, as long as the whole zooecium. The specific name chosen 

 refers to the serrate inner border of the primary orifice, a character which is unique in this genus, as far 

 as my knowledge goes. The species shows resemblances to L. edax Busk and to L. contracta Waters, 

 but there are many differences which distinguish it. 



Vineyard Sound and tlie lower part of Buzzards Bay, common, 5 to 15 fathoms, Muskeget Channel 

 in 7 fathoms. Great Round Shoal in 8 fathoms. Crab Ledge in 14 to 20 fathoms. I have also seen speci- 

 mens in the United States National Museum collection from Nantucket Shoals and from Lcng Island 

 Sound. 



Genus MUCRONELLA Hincks, 1880. 



KEY TO SPECIES. 



1. Avicularia present, one on either sideof the aperture, which is large; ovicell wanting pavonella. 



Avicularia wanting, ovicells present 2. 



2. A pointed mucro behind the orifice, peristome not raised unusually high, zooecia small, but little 



convex, becoming flat with age peachii. 



Peristome raised very high, forming a spout-line or tubular erect structure, the mucro very large 

 and broad, zooecia larger, very convex, not becoming flat with secondary calcification, .ventricosa. 



