72<i lAiii; sKor.sisKiir, 



liiscriptinii: - Si-f C. W . .Mi'i.i.HU, l<iO()ii, \>. 117. 



Sup}>lnncHt(iri/ description: — .M ale: — 



S h oil: — JA'iigtli: Airording to (J. W. Mni.l.i;i; ,'{,7—4,1 nun.; my .s]ic(iiiiciis measured 

 4.0 — 1,25 mm. Lengtli : height about 2.1 : 1; Icnutli : l)rc;ulth al)()ut 2,4 : 1. Seen iioiii 

 the side (see fig. 1) it is ol about tl\e same type as in ( '. pliiillniKt (i. \V. Mf^M-liH. It 

 differs from tliis in the following re.spects. The anterior part of the dorsal margin is partly 



Fig. CXX.WIII. — Cunchoecia symmelrica G. VV. Muller, <S. — 1. Shell seen from the side: 19 X. 2. Shell seen 

 from below; 16 X. 3. Anterior pari of the left valve seen from inside: H9 X. 4. A part of the selvage just inside 

 the lateral corner gland; 833 X. 5. A part of the posterior margin of the shell seen from inside: .5fi7 X. (From 



specimens from staliim r.'i 1>.) 



covered by the shoulder vault. The ventral margin is somewhat, though only rather slightly, 

 concave. The lateral corner glands have their exits on a large conical peg, which is of about 

 the same size and type on both valves and which extends rather considerably beyond the margin 

 of the shell. The processes at the postero-dorsal corner of the shell are somewhat, though only 

 rather slightly, shorter. Seen from below it has its greatest breadth at about the middle 

 and the anterior part somewhat larger than the posterior part. The side contours are rather 

 evenly curved except just behind the middle, where they undulate rather weakly. Both the 

 back and front ends are pointed; the rostral process on the left valve is only slightly larger than 

 that on the right valve; see the appended fig. 2. The shoulder vault is well developed and is 

 rounded. For the sculpture see G. W. Muller. The surface of the shell has a very 



