334 BIOLOGICAL SURVEY OF 



tions 10, 13, 33, 36, 39, 40, 60, 69, 83, 89, 120, 121, and shore 

 station 42. It is difficult to state the distribution of S. con- 

 cimia, as it has been considered an extremely variable species, 

 and probably several species have been recorded under this 

 name. The Lepralia belli of Dawson (1859, p. 256) is probably 

 correctly indicated as a variety of concinna, as it seems to 

 differ only in the manner of secondary calcification and not in 

 any primary character. Our specimens from Mt. Desert 

 Island seem to come close to this variety. On the other hand, 

 some of the records for concinna by Osburn (1912, p. 247, and 

 1912 a, p. 283) for Crab Ledge, Cape Cod, and for Labrador, 

 Newfoundland, and Nova Scotia are confused with the follow- 

 ing species. Figure 67 a of plate 27 of Osburn (1912) prob- 

 ably represents another species. It resembles the variety 

 gracilis of Hincks (1880), which Busk later raised to a new 

 species (1884, p. 154), graciosa, if indeed Busk was not dealing 

 with still another form. I have in my collection specimens 

 sent me by Sir Sidney F. Harmer from the English coast 

 which appear to be the true concinna, and some of my speci- 

 mens from Cape Cod and Shoal Tickle, Labrador, as well as 

 those mentioned above from Mt. Desert Island, compare well 

 with Harmer 's specimens. Hincks has listed it and figured it 

 as well (1892, pi. 8, fig. 6, var. belli), but his earlier figure 

 (1889, pi. 21, fig. 4), showing the front of the zooecium per- 

 forated, appears to me to be another species. 



The true concinna has the zooecia rather regularly disposed 

 in lines, the frontal in young cells somewhat arched and finely 

 granular, with a varying number of marginal pores, ordi- 

 narily 8 to 12. The suboral avicularium resembles closely in 

 form and position that in the genus Porella, but a wide lyrula 

 (nearly half as wide as the aperture) is present on the proxi- 

 mal border of the primary aperture. In secondary calcifi 

 cation, the frontal surface becomes thickened and more 

 coarsely granular, forming an almost level crust, through 

 which the marginal pores show in their original position. The 

 ooecium is subglobose and imperforate (sometimes a single 

 median pore may be present near the aperture), granular, 



