

RECENT BRITISH OSTRACODA. 



399 





two curved transverse furrows; colour reddish brown. Animal precisely like that of ( 

 pellucida. 

 Length -£$ in. 



Hab. Chiefly in the brackish water of estuaries and salt marshes. Girdler sand, Thames, and at Tweed- 

 mouth (Mr. E. C. Davison); in salt marshes at Hylton on the Wear, J arrow on the Tyne, Seanm 

 Sluice, and at the mouths of the Wansbeck and Ahie, Northumberland (G. S. B.). 



* 



The great similarity between this and the foregoing species caused me, until wry 

 recently, to regard the one as a merely littoral or brackish-water variety of the other. 

 I have been induced to alter that opinion, chiefly by finding, in a gathering from the 

 Girdler sand in the estuary of the Thames, the two forms living together abundantly, 

 and retaining very perfectly their distinctive characters. The points which may be 

 chiefly relied on as characterizing C. castanea are, the more arcuate dorsal margin and 

 greater comparative height of the female, the median position of the gmtest width of 

 the carapace, and, in the male, the perfectly straight dorsal margin, and inuch-narrowrd 

 hinder extremity— lastly, the sculpture of the shell-surface, which consists of closely Bet 

 rounded (not oblong) impressions. The list of habitats here given is doubtless very 

 imperfect; the species must often have been passed by without special notice as a form 

 of C. pellucida. 



5. Cythere tenera, n. sp. (Plate XXVIII. figs. 29-32.) 



British type. Distribute : Recent-G^t Britain, Bay of Biscay. *W-Glacial, Norway. 



Carapace of female almost exactly similar in form to C. pellucida but much smaller 

 the superior margin somewhat more arched ; the surface smooth and having no trace of 

 any transverse sulcus. The shell is very closely and delicately punctate and hears a 

 distant and minute elevated papiHte. The length is »^^"^ £ 

 The outline as seen from above is regularly ovate. Animal unknown. 

 Shell of the male narrower, and tapered posteriorly. 



Length A in. • _ _ , .__.,,..„„. , rm,™,, 



Harbour, Durham 

 {Mr. E. C. Davison) : the Minch {Rev. A. M 



. ^ j * r n pJI„rida bv its much smaller size, v 



This species is easily distinguished from C. peW^da y ^ ^ ^ ^ 



There can, 



flue punctation, and absence of furrowing. M-» -> ^ l ^ obserTed 



specific rank : all the specimens I have seen are undo ^ ^ ^^ ^.^ 



no forms intermediate in character between tt anc I e >u 



The young of C. pellucida, even in their very earl stages, ai q 

 and those of C. castanea are mostly also of dark colom . 



6- Cythere badia, Norman. (Plate XXIX. figs. 56-59.) 



i •„ aaai) r> 48, pi. iu- n o s - 13 -10 - 

 Cythere badia. Norman. Ann. & Mag. Nat. Hist. vol. a. (1862) ]'• . P 



? 



cicatricosa, Sars, loc. cit. p. 33. 



-/• 



r t Britain and Ireland, 



British type. Distribution: Recent-Xonvny, W» :uu l Ireland. 



/•mwV— Raised beaches and glacial clays, Nor* ay, » 



