y 



,/ 



474 /" MR. G. S. BRADY'S MONOGRAPH OF 



of t]ie latter species, I considered tlie two to be identical. But a comparison with Nor- 

 wegian specimens, kindly communicated by Herr G. 0. Sars, leads me to believe them 

 distinct. The characters in which C. abyssorum chiefly differs from the present species 

 are as follows : — The extremities, especially the anterior, as seen from above, are more 

 abruptly truncate, the angles somewhat produced, and the general outline more com- 

 pressed ; seen from the side, the outline is more evenly ellijotical ; the surface of the 

 shell is much more profusely punctate and the puncta larger. 



2. Cytherella LiEVis, Brady. (Plate XXXIV. figs. 15-17.) 

 Cytherella lavis, Brady, Brit. Assoc. Eeport, 1866, p. 211. 



Valves, as seen from the side, subovate, highest in front, greatest height equal to 

 about three-fourths of the length ; anterior extremity broadly rounded, posterior rather 

 narrowed ; superior margin M^ell arched, sloping steeply behind ; inferior sinuated in 

 the middle. Outline, as seen from above, ovate ; sides and angles well rounded. Sur- 

 face quite smooth and devoid of sculpture. Colour yellowish white. 



Length ^7- in. 

 Hab. The Minch, 60 fathoms. 



One valve only was found, in the same gathering as the previous species. 



APPENDIX. 



The following species were, for various reasons, not noticed in the foregoing pages : — 



Bairdia ful\a, nov. sp. (Plate XXVIII. fig. 21.) 



Carapace, as seen from the side, subreniform, highest in front of the middle ; greatest 

 height equal to rather more than half the length ; anterior extremity rounded ; posterior 

 somewhat narrowed, rounded below ; superior margin boldly arched, inferior sinuated in 

 the middle. Seen from above, compressed ovate, widest in the middle ; extremities 

 equally acuminate ; width much less than half tlie length. The right valve is much 

 larger and higher than the left, and overlaps considerably, both on the dorsal and ventral 

 margins ; it is also much less angular in outline. Surface of the shell finely and closely 

 punctate. Colour yellowish brown. Animal unknown. 



Length -^5- in. 



My first acquaintance with this species was 'derived from a single valve of the left side 

 found among shell-sand from Houndstone. Prom its shape and the characters of its sur- 

 face-marking, I supposed that it might perhaps be referable to a variety of, or to some 

 species nearly allied to, Cytheridea punctillata, and I therefore figured the valve in jux- 

 taposition with that species. But having more recently seen a perfect specimen, found 

 l)y Mr. Bobertson at Shetland, as well as one or two fossil examples, I have no hesita- 

 tion in describing it as an entirely new species of Bairdia. It will be fully illustrated 

 in the ' Monograph of Posttertiary Entomostraca.' 



