56 THE VOYAGE OF H.M.S. CHALLENGER. 



[PI. VIII. figs. 1 and 2, a-d. a Carapace seen from left side, b from above, c from 

 beloAv, d from front, e right valve, /left valve. Fig. 1 magnified 40, fig 2, 30 diameters.] 



13. Bairdia milne-edwardsi, G. S. Brady (PI. X. fig. 4, a-g). 



Bairdia milne-edioardsi, Brady, Les Fonds de la Mer, torn. i. p. 139, pi. xvii. figs. 3, 4. 



Carapace, as seen from the side, subtriangular, height equal to two-thirds of the 

 length ; anterior extremity slightly rounded, ending suddenly in an obtuse angle above ; 

 posterior produced into a median conical beak ; dorsal margin strongly arched, gibbous, 

 sloping with a steep curve to either end, sinuated in front, ventral margin slightly convex ; 

 seen from above the outline is lozenge-shaped, twice as long as broad, with a distinct 

 lateral sinuation before and behind the middle, extremities obtuse, mucronate ; end view 

 liroadly ovate, height one-third more than the width. Surface of the shell densely 

 punctate with small circular impressions. Length, l-25th of an inch (l mm.). 



The only dredging in which I have seen specimens at all certainly referable to this 

 species is one from a depth of 1070 to 1150 fathoms, on a muddy bottom, off St Vincent, 

 Cape Verde. 



The types described in Les Fonds de la Mer, were also got at St Vincent. Some 

 of the shells, which I have referred, with not a little hesitation, to Bairdia foveolata^ 

 make a very close approach to the present species : that figured in fig. 4 a-c, 

 where, though the lateral outline is very difi"erent, the sinuous dorsal aspect is exactly 

 the same, is an instance of a debateable form ; judging from the regularly arcuate dorsal 

 margin, the dentated anterior, and the very slightly produced posterior extremity, one 

 would have placed it without hesitation apart from Bairdia milne-edwardsi, but the 

 other aspects of the shell leave one in doubt about the matter. I have seen only one 

 specimen, I think, of this questionable form : figures d-g must be looked upon as repre- 

 senting the typical form of the species. 



[PL X. fig. 4, a-g. a Carapace (variety ?) seen from left side, b from below, c from 

 front, d (typical form) seen from left side, e from above, f from below, g from front. 

 Magnified 40 diameters.] 



14. Bairdia victrix, G. S. Brady (PL X. fig. 5, a-d). 



Bairdia vidrix, Brady, Les Fonds de la Mer, torn. i. p. 152, pi. xviii. figs. 17, 18. 



Carapace tumid, gibbous ; seen from the side subtriangular, height equal to rather 

 more than two-thirds of the length ; anterior extremity rounded, posterior obliquely 

 truncate and produced into a prominent obtuse beak ; dorsal margin very boldly arched, 

 ventral more or less convex, and often irregularly sinuous towards the posterior extremity; 

 the margins of the right valve are often beset at the two extremities with numerous 

 short, obtuse teeth ; seen from above the outline is broadly ovate, more than twice as 



