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I have great pleasure in naming tliis tine and characteristic deep-sea species after the 

 leader of the "Siboga" expedition, Professor Max Webkr. It was taken at a depth of 560 m., 

 and thus may really be considered a deep-sea species. 



It is a well-marked species: it shows a certain resemblance to D. orthogonia and belongs 

 to the same section of the genus, but it differs from it by its size, as well as by the shape 

 of the tergum and of the disc forming the base of the carina. 



The present species and D. sessilis Hoek, dredged by the "Challenger" in the Atlantic, 

 near the Azores, at a depth of 1000 fathoms, are the only known species of the genus Dichelaspis 

 living at considerable depths. 



5. Dichelaspis Vei'sliiysi n. sp. PI. Ill, fig. 8 — 13. 



Capitulum compressed, apex produced. Scuta with the basal segment much narrower 

 than the occludent seo'ment and more than half as lona:. Tersfa with three distinct marginal 

 projections and a fourth one very small. Carina terminating downwards in an oval disc-like cup. 



General appearance. Capitulum flat; valves small, a large part of the surface of 

 the capitulum remaining uncovered. Valves covered by membrane so as not to be seen distinctly 

 without isolating them. Peduncle cylindrical not quite half the length of the capitulum (PI. Ill, fig. 8). 



Scutum (fig. ga). It consists of two bars placed in most of the specimens at right 

 angles to each other, in one of the specimens (figured in fig. 9) at an angle of more than 90°. 

 The point of junction is perfectly calcified. The basal segment uniformly narrow, the occludent 

 segment, which is less than twice as long as the basal segment, grows much wider towards 

 the apex. It is flat with the apex obliquely truncated. 



Tergum (fig. gd) of a triangular shape, with three ridges terminating in three 

 prominences of unequal length. Seen from the outer side the three divisions are separated from 

 one another by distinct, even deep furrows. The fourth ridge or prominence is extremely small 

 and situated at the carinal side just above the apex of the carina. 



Carina (fig. gc). Much bowed, even slightly more than is the case in D. TVederi, 

 long, not very narrow, keel-shaped in its basal part and with a flattened central ridge above 

 the middle to as far as the apex. Internally the valve is concave. The basal portion is embedded 

 and forms a cup of a very peculiar shape: it is oval with at each side a small wing, like the 

 small handles of a bowl (PI. II, fig. \oa, while fig. lo^^ shows the cup-shaped basal portion 

 of a specimen of D. orthogonia with the same enlargement, seen from the same side). 



Peduncle short, cylindrical-, length about one third that of the capitulum. In most of the 

 specimens the chitinous outer wall is transparent and surrounds the muscular part like a wide sack. 



Size. Length of the capitulum in one of the larger specimens 6,3 mm. when measured 

 from the tip of the tergum to the base of the carina. Several specimens, however, are considerably 

 smaller. The largest specimen is over 7 mm. 



The m o u t h and its parts in general resemble greatly the same parts in D. orthogonia : 

 crest of the 1 a b r u m with a row of small bead-Hke teeth ; palpi with the two sides parallel, 

 bearing towards the one side numerous very long bristles. 



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