

RECENT BRITISH OSTRACODA. 



<H0 



side, oblong, highest in the middle, greatest height equal to less than two-thirds of the 

 length, narrowed and rounded in front, obliquely truncate behind; superior margin 

 strongly arched, inferior rather convex. Outline, as seen from above, broadly ovate 

 widest behind the middle, extremities pointed ; greatest width equal to more than half 

 the length. End view triangular, equilateral, broad at the apex ; base flat , sides decidedly 

 concave. The shell is obscurely punctate and rugose, and has two more or less strongly 

 marked rounded ribs running from the central portion of the ala to the extremities of the 

 hinge-margin, and forming, when viewed from above, two large rounded nodes; the ala 



itself is more angular than in the preceding species. Animal unknown. 



Length tAt in. 



b"-" 5 



Mr. J. G. Jeffi 



(Dr. Alcock). 



4. Cytheiiopteron punctatuh, n. sp. (Plate XXXIV. figs. 45^8.) 



Cytheropteron tiicorne, Brady, Brit. Assoc. Report, 1866, p. 208. 



Outline, as seen from the side, very similar to the preceding ; but the posterior margin 

 is broader and more produced above, and the lateral ala much more exserted and endim: 

 suddenly, behind the middle, in an acute angle. Outline, as seen from above, rhomboidal, 

 rectangular behind the middle, thence tapering to the acuminate posterior extremity ; or 

 it may be described as consisting of two equilateral triangles applied to each other by 

 their bases, the larger being in front; greatest width behind the middle and equal to 

 nearly three-fourths of the length. Surface of the shell minutely punctate. 



Length A in. 



&*-" 5 5 



M. Norman) , and off Ormeshead (M; 



I was at one time disposed to refer this species to a fossil form described by Herr 

 Bornemann under the name Cythere tricornis; and in outline the two are, indeed ven 

 similar ; but the fossil species seems to have no punctation of the surface ; and as it differs 

 slightly in other respects, it seems better to keep it distinct. 



5. Cytheropteron mtjltiforum (Norman). (Plate XXIX. figs. 38-42 



midtifi 



If S * 



Assoc. Report, 1864, p. 192. 

 Atlantic type ? Distribution : Recent— Britain, Ireland. , . , . 



Carapace of the female, seen from the side, oblong, rhomboulal, equal m 1 e n« 

 throughout ; height equal to more than half the length ; ventral ala not very p— 

 Extremities irregularly and obtusely rounded, the anterior obhque and formmg an o tn 



ght 



junction 



ith the dorsum ; superior and inferior mar,ins parallel and 



s junction witn uw uux.u^, ~r~~ «,ddenlv tapering pointed 



—*-„. Seen from above the outline is subhexagonal, with suack my lapei .. & t 



b "v. oeeu nom duove, tiic im^th ; hinge-margins 



extremities- neatest width equal to much more than nail tne iui i , o ■ 



unities , greatest wicitn equa End view subtnangular, 



depressed behind the middle so as to form a longitudinal sulcus 



the three sides convex, apex and base centrally emargmate. I»q~ « <- - — 

 oi A .-, ., - i— «««.UaL Shell-surface marked with close iv set 



gated; sides, as seen from above, parallel 

 Vol. xxvi. 



3 



