Smith and Harger — St. George's Banks Dredgings. 5 1 



coming faint toAvard the beak. Auricles unoqiuil,,tliat of the upper 

 valve small, and a little projecting posteriorly, much longer and more 

 prominent, with a deep, curved emargination anteriorly, its surface 

 with concentric lamellae and radiating rows of small, conical vesicles ; 

 that of the lower valve with a deep, angular byssal notch anteriorly, 

 its surface with concentric lamelhi3 and faint radiating ridges. Color 

 yellowish white. Length, 7-5""" ; height, 8-0""" ; thickness, 2-5""", 



East of St. George's Banks {g), in 430 fathoms, dead but fresh 

 valves; and north of the Banks, locality {s), 150 fathoms, living. 



Pera crystallina VerriU. 



Clavelina crystallina Moller, Naturliistorisk Tidsskrift, vol. iv, p. 95, 1842. 

 Pera imllucida Stimpson, Proceedings Boston Soc. Nat. Hist., vol. iv, p. 232, 1852. 

 Pera crystallina Verrill, American Journal of Science, III, vol. iii, p. 213, pi. 8, fig. 

 9, 1872. 



Plate VIII, figure 1. 



This species was described by Stimpson from specimens, adhering 

 to stems Sertidarelkt polyzonias, variety gigantea, taken in 30 fathoms 

 on St. George's Banks. Professor Verrill records it from Murray 

 Bay, Gulf of St. Lawrence. 



Glandula arenicola Verrill. 



American Journal of Science, III, vol. iii, pp. 211, 288, 1872 ; Report on the Inver- 

 tebrate Animals of Vineyard Sound, in Report of U. S. Commissioner of Fish and 

 Fisheries, 1873, p. 701, 1874. 



This species, which was dredged by us in immense numbers in 28 

 fathoms (haul c), has also been dredged, by Dr. Dawson, at Murray 

 Bay, Gulf of St. Lawrence, by Mr. T. M. Prudden, in Buzzard's Bay, 

 and off New London, Conn., by A. E, Verrill. 



Thyone scabra Verriii. 



American Journal of Science, 111, vol. v, p. 100, 1873. 



Thyone fusus ? Verrill, American Journal of Science, III, vol. v, p. 14, 1873 (mow 

 Koren). 



Body fusiform, gi-adually tapered behind, with a long, slender, pos- 

 terior portion, covered throughout with very numerous, rather rigid, 

 slender, scabrous papillae ; skin rather rigid, scabrous with small, 

 rough points, which project from the plates. Tentacles ten ; eight 

 large ones much elongated and arborescently divided from near the 

 base ; the two small ones are very short, nearly sessile, subdivided 

 from the base. The calcareous plates of the skin are very flat, some- 

 what imbricated, irregularly oval, triangular, or subpolygonal, with 

 an undulated or crenulated margin, pierced by about 20 to 24 unequal 

 round openings, tAvo or three central ones larger than the rest, the 



