MARINE OSTRiCODA FROM MADEIRA. 599 



Cytherura maculosa, sp. n. (Plate XXII. figs. 6, 7.) 

 Shell, seen laterally, oblong, subreniform, highest in the middle 

 (fig. 6), height equal to half the length ; anterior extremity evenly 

 I'ounded, posterior produced in the middle into a wide obtusely 

 pointed beak ; dorsal margin evenly arched throughout, ventral 

 i-ather deeply sinuated in the middle, prominent behind, thence 

 sloping with a sinuous curve vip to the beak : seen from above 

 (fig. 7) oblong, three times as long as broad, lateral margins 

 parallel throughout the greater part of their length, converging 

 towards the front; anterior extremity broad and truncated, 

 posterior produced into a wide median beak. Surface of the 

 \'alves marked with faint loirgitudinal striae and with minute, 

 closely-set, impressed pits ; in most cases the middle of the valve 

 l)ears a dark transverse blotch of irregular shape, but this may be 

 absent or much reduced in size. Length 0'39 mm. 

 Several specimens from low-water mark. 



Cytherura cribrosa, sp. n. (Plate XXII. figs. 4, 5.) 



Shell, seen from side, oblong, rhomboidal, height scarcely equal 

 to half the leogth ; anterior extremity well rounded, posterior 

 produced above the middle into a very large and rather sharp 

 beak (fig. 4) ; dorsal margin straight throughout almost its whole 

 length, venti-al rather deeply sinuated in the middle, behind 

 which it bulges ventrally : seen from above, oblong, subovate, 

 width scarcely equalling half the length (fig. 5), rather abruptly 

 tapered and subacuminate in front, posteriorly abruptly truncated 

 and produced into a large central beak. Surface of the shell 

 honeycombed with la,rge subrotund fossae, which are ari'anged in 

 irregular longitudinal rows. Length 0*44 mm. 



Many specimens dredged in 50 fathoms. 



Cytherura fossulata, sp. n. (Plate XXII. figs. 8, 9.) 



Shell, seen laterall}^, oblong, rhomboidal, of nearly equal height 

 throughout, length equal to more than twice the height (fig. 8) ; 

 anterior extremity obliquely subtruncate, often indented below 

 the middle, the sinuations bounded by two small nodules, two 

 rounded tubercles near the anteiior extremity, jusb within the 

 superior margin, over the I'egion of the eyes ; posterior extremity 

 oblique, produced above the middle into a large upward-pointing 

 beak ; dorsal margin perfectly straight, ventral nearly straight, 

 with a slight ventral convexity : seen from below (fig. 9) the 

 outline is that of an a.rrowhead, the lateral acute prominences 

 situated near the posterior third, the width at that point equal to 

 more than half the length of the shell, behind these angles the 

 shell is suddenly narrowed, forming a rounded hinder end which 

 terminates in a large median beak : anteriorly the lateral margins 

 converge with a deep cui'vature to the front, ending in a wide 

 bluntly rounded extremity. The surfM.ce of the shell is variously 

 and very irregnlarl}' marked Avith furrowed undulations more or 

 less transverse in their direction, and by a conspicuous curved 

 longitudinal crest which ends behind the middle near the ventral 



