834 rnoc'.KEDiNos OF THE NATIONAL MUSEUM. VOL.XX. 



CHLAMYS BENEDICTI Verrill and Bush. 

 (Plate LXXXIV, ligs. 1, 2.) 



(hlnmi/s ln'Hi-<Hrli. \'Ki:i:n.L and BUSH, in VERRILL, Trans. Conn. Acail., X,pp.74, 

 91. IS'.IT. 



Shell small, higher thaii long; anterior auricle much larger than the 

 posterior, with a deep byssal uotc.li in the lower or right valve. The 

 dorsal margin is straight and but slightly oblique; the posterior auricle 

 in the right valve is decidedly angular, with its outer end slightly 

 incurved and seriated by the termination of the radial ribs; the ante- 

 rior auricle is considerably prolonged, angulated at the upper corner, 

 obtusely rounded at the end and deeply notched where it joins the 

 main shell; it has four strongly marked radiating ribs, besides the 

 dorso-marginal fold; below these there is a slightly concave space cor- 

 responding to the byssal notch; on the body of the shell there are 

 from four to seven sharp serrations along the lower margin of the 

 notch. In the upper valve the anterior auricle is broad and decidedly 

 angular, the dorsal and outer margins forming less than a right angle; 

 its surface is covered with five or six strong radiating ribs decussated 

 by more numerous, finer, concentric raised lines. The anterior and 

 posterior margins of the body of the shell slope about equally and form 

 an acute angle; the ventral margin forms a regular semicircular curve. 

 The entire surface in both valves is crossed by strongly raised, rather 

 close, radiating ribs separated by rather wide, deep grooves and are 

 decussated by regular, raised, concentric lines, which are scarcely appar- 

 ent on the ribs, except on very young shells, but there are rather 

 strong, elevated, spine-like points arranged along the ribs in pretty 

 regular, concentric lines, especially near the margins; these become 

 higher and more pointed anteriorly and are frequently nearly obsolete 

 in the middle portion of the lower valve; the ribs project at the mar- 

 gin as blunt points or serrations; on the inner surface there are radial 

 grooves corresponding to the external ribs. The hinge-margin is thin, 

 with a slender ligamental, submarginal groove and a small, triangular 

 resilial pit in the center. The color is variable; the single valve from 

 station 2571 is uniform lemon yellow ; those from the other locality are 

 chestnut or reddish brown and variegated with paler and sometimes 

 white blotches. 



Length of the largest specimen, 5.5 mm.; height, 6 mm.; length of 

 dorsal margin, 4 mm. 



A few live young specimens, among Foraminifera, stations 2369 to 

 2374, in 25 to 27 fathoms, and a single valve, station 2571, in 1,356 

 fathoms, 1885. 



This species is a typical Cklnmys, allied to C. varia of Europe, but 

 when compared with young of that species of the same size the radial 

 ribs are found to be fewer and coarser, and there are other differences 

 which render it probably that they are distinct. It differs from the 

 young of C. inlainlica in the number of ribs and shape of the auricles. 



