e witli the rid il"- roof of the carina: these ridges are 



distinct in the pecimens .ts in thal of the "Challenger". I sh< 



mention also that the scales . • i" t li« - peduncle which in the ■Challenger" specirnen are pla« 

 jn i-i i .t ..ul.ir rows, in the largesi "Siboga" specimen may be said to form longitudinal 



., in the smaller specimen, however, this can hardly 1"- said. 



Wuii regard to the shape of the carina I found that this species belongs also to the 

 ie umbo of the carina is not quite at the apex of the valve, but at a short distance 

 from it. In this regard it much resembles Sc. polymorphum with which it corresponds also in 

 ral other regards. 



Finally 1 must point < uit. that the chitinous interspaces b( tween the valves which wi 

 rather broad in the ■Challenger" specimen, are much more prominent in the larger "Sibi 

 specimen (from Station 175 than in the smaller the one figured which was taken at Station 



Th. structure of the animal of the only specimen taken 1>\ the ■Challenger" was not 

 studied; 1 have thought it useful, therefore, to examine one of the ■Siboga" specimens. 



Mouth not very bullate; «rest of the labrum with a row of very small knobs at the 

 of the teeth; pal pi conical, rather small, with a group of short bristles at the tip and 

 a couple of very short spines on the internal margin about the middle of its length. 



Mandibles with three teeth; distance between 1 and 2 slightly greater than that 

 between 2 and 3; inferior angle close to tooth 3, short, rounded and delicately pectinated. 

 Short hairs are planted along the under margin. 



Maxillae with a not very distinct notch aboul or a little above the middle of the edge; 

 above the notch three unequal spines, in the notch (or as fourth spine above the notch) one 

 spine; beneath the notch six spines. Apodeme stout, rather long and broader at the extremity. 

 Outer maxillae rounded, with the bristles divided into two separate tufts; the orifice 

 giving entrance to the bod) cavity at the end of a long and Hat process, transversely cut off 

 at the extremity. 



Cirri. First pair short, not separated from the second by an interspace; rami unequal 

 in thickness and slightly in length: the shorter ramus has about S broad, the longer 10 more 

 cylindrical segments. The lust segment in both rami is much longer than the others, the last 

 one considerably shorter. In both rami the segments are thickly clothed with spines. 



>nd cirrus (in the specimen investigated both rami broken ofl at one side. and one 



ramus broken off at the other side. The only remaining ramus has [7 segments, the first of which 



is rather long, the following nearly quadrilateral, the last ones cylindrical and much narrower. 



Sixth cirrus has 22 segments in both rami: the first one verj long. then come four 



or five nearly quadrangular segments, the following nine growing longer and narrower, the 



beinc the longest o,' all and nearly five times as long as broad. The last sesrments qtow 



still narrower but diminish in length: the last is very narrow and tapers towards the extremity, 



where three short spines an- planted. The number of pairs of s|iines found on the front side 



inent is from three to seven; this number is largesl at the I4 ,h segment. 



indal appendages long and narrow. tapering towards the extremity and consisting 



or o (right side segments, of which the penultimate is the longest. Near the 



84 



