878 PROCEEDINGS OF THE NATIONAL MUSEl'U. VOL. xx. 



minute or nearly abortive, occupying 1 a slight notch in the dorsal 

 margin under the beak, external to the series of teeth, which are inter- 

 rupted only by a small, thin edentulous space. Pallial sinus small. 

 Siphon tubes short. Labial palpi large, broad, crescent-shaped, with 

 long tentacular appendages. Gills small, triquetral. 



We consider this group worthy of generic rank. It appears to be 

 more nearly allied to Mnlletia than to Yoldiaur Leila. We can find no 

 generic characters to distinguish Ball's typical species (N. corpulent a) 

 from N.pusio, which was the type of the section, Saturnia, proposed 

 by Seguenza. They agree closely in form, external sculpture, arrange- 

 ment of the teeth, and structure of ligament and resilium. The name, 

 Saturniaj being preoccupied by Schrank, 1802, we have adopted Ball's 

 name for both of his sections. 



The following species appear to belong here: 



N~. corpulenta Ball (type), and N~. quadrangularis (Ball), West Indies; 

 N.sericea (Jeffreys), Ireland and Portugal; N.pusio (Philippi), Medi- 

 terranean and West Indies; N. subovata Verrill and Bush, from off 

 Cape Hatteras, North Carolina, northward. 



NEILONELLA SUBOVATA Verrill and Bush. 



(Plates LXXX, fig. 10; LXXXII, figs. 3, 4.) 



Yoldia sericca JEFFREYS, var. strlolata VKRKILL, Trails. Conn. Acad., VI, p. '226, 

 1884. VERRILL, Expl. Albatross, Report U. S. Com. Fish and Fisheries j'or 

 1883, p. 576, 1885. 



Neilonella- suboi-ala VEKRILL and BUSH, Anier. Jouru. Sci., Ill, p. 57, figs. 7, 8, 22, 

 January, 1897. 



Shell somewhat swollen, subovate, with the dorsal margin angulated 

 and the umbos somewhat prominent. The antero-dorsal margin is 

 somewhat convex, pinched up at the edge, and sloped gradually to the 

 evenly rounded anterior end; ventral margin is broadly and nearly 

 evenly rounded throughout, without any sinuosity, and forms a blunt 

 point at its junction with the postero-dorsal margin, which is nearly 

 straight or slightly convex for the greater part of its length, with the 

 edge thin and pinched up. The umbos are somewhat prominent and 

 the beaks curve strongly inward and incline a little backward at the 

 tip. The ligament is well developed, dark brown, and as seen in a 

 dorsal view, fills a narrow, lanceolate excavation in the margin just 

 behind the beaks. In an interior view it is conspicuous behind the 

 beaks and occupies a curved notch immediately under them, and ex- 

 tends forward for a short distance in a thin, marginal groove. The 

 resilium is abortive or nearly so; in many cases it appears to be repre- 

 sented by a minute black speck, adherent to the ligament, and occu- 

 pying a minute indentation in the edge of the hinge-margin directly 

 beneath the beak, external to the series of teeth. The hinge-margin is 

 broad and rather strong, becoming very narrow below the beak but 

 without a distinct notch or choudrophore; the posterior portion is 



