420 



TAGE SKOOSl^ERG 



other and almost parallel, both continuing down to the rostrum. Tlie two other ridges run more 

 parallel to the longitudinal axis of the shell, one somewhat above, the other somewhat below 

 half the height of the shell. The former continues anteriorly to the rostrum, where in most 

 cases it joins the dorsal ridge; posteriorly it joins the ridge that runs along the ventral margin 

 on the posterior beak-like process of the shell ; the anterior part of this ridge is weakly and fairly 

 uniformlv curved dorsally; behind the middle of the shell, on the other hand, it is very irregular 

 with at least two very striking, nodose, projecting corners. The latter, the ventral one of the ridges 

 that run more parallel to the longitudinal axis of the shell, is almost straight and suddenly comes 

 to an end posteriorly a short distance in front of the posterior beak of the shell with a rather 

 strongly projecting protuberance; anteriorly just behind the rostral incisur it is joined by means 

 of a low but distinct transverse ridge both to the ridge running most dorsally to it and to the 



:v^"i> 



Fiff. LXX\'1I. — /'/(. (Sflrroconcha) Appellofi n. sp., ?. — 1. Lel'l valve spfn rrom the 



light); 2:i X. 2. Shell seen Irnm below; I '1,5 >;. 



^iile (in reflected 



ridffe that runs along the ventral margin. The foveolae are sometimes considerably less developed 

 than is shown in the accompanying figure. The ridges, like the bottoms of the foveolae, have 

 a sculpture with small cavities, sometimes very difficult to observe (in some cases not even 

 existing?). The surface of the shell is sjjarsely furnished with small hairs, more numerous and 

 somewhat longer near the margin of the shell. Pores of the surface are found to a moderate 

 number; they are small and difficult to observe. Seen from inside the posterior beak- 

 like process appears to be slightly hollowed out in the shape of a siphon. Medial bristles: 

 The row of bristles on the rostrum is rather sparse; a number of bristles in this row do not seem 

 to have any IcMig distal secondary bristles. The bristles on the posterior portion of the list are 

 difficult to observe with certainty; they seem to exist in moderate number and not to be arranged 

 in clear groups. Between tlie list and the posterior margin of the shell no bristles seem to occur, 

 nor is any pocket-like formation observable here. 



First a n t e n n a (fig. 4): — Of the three bristles on the second joint the posterior 

 one is the longest, being in most cases about as long as the total length of the third to the fifth 

 or the third to the sixth joints; the lateral one is the shortest, in most cases about as long as 

 the total length of the tliird and lourth joints. The third joint has two anterior bristles and (me 



