r* 



1:50 MR. G. S. BRADY'S MONOGRAPH OF 



1. BUOTTHEBE declivis (Norman). (Plate XXVII. figs. 22-26, 52-55.) 



Cythere declivis } Norman, Nat. Hist. Trans. Northumb. & Durh. vol. i. p. 16, pi. v. figs. 9-12, and Brit. 



Assoc. Report, 18G1, p. 192. 

 ? Cytkeropsi* tenuttesta, Sars, loc. cit. p. 59. 



British type. Distribution : Recent — Norway, Great Britain, and Ireland. Fossil — Glacial, Scotland. 



Valves of the female as seen from the side subtriangular, broad and well rounded in 

 front, tapering to a narrowly rounded point behind ; greatest height in the middle, equal 

 to considerably more than half the length. Superior margin boldly arched in front of 

 the middle, thence sloping steeply to the posterior extremity; inferior margin gently 

 sinuatcd in front of the middle. Outline as seen from above oblong, ovate; greatest 

 width equal to about half the length, situated at the posterior third ; extremities pointed. 

 End view somewhat pyramidal, the base rounded. Shell pellucid, smooth, or marked with 

 very fine puncta, and beset with distant round white papillae. Lucid spots three or four 

 in a transverse row, with two (usually coalescent) in front. Carapace of the male much 

 more elongated, and less arched on the dorsum ; height equal to less than half the length. 

 " "pper antennae moderately long, the second joint much shorter than the united length 

 of the three following ; last joint narrow and linear. Internal lobe of the first maxillae 

 forming a very small bisetose tubercle ; external lobe or palp not larger than the other 

 1 wo, the last joint much longer than the preceding. Branchial lamina sub quadrangular, 

 the four external setse thicker than the others, and more densely ciliated. Feet very 

 lender, terminal claws very long and narrow. Copulative organs very small, distal 

 portion obtusely rounded." This description of the animal, quoted from G. O. Sars, applies 

 to the male only of E. tenuitesta. 



I 



Length -h in. 



» v " 45 



Hi 



(Mr. Jeffi 



Donegal Bay (Mr. E. C. Davison) ; Lerwick {Mr. D. Robertson) ; Aberdeenshire coast {Mr. Dawson) ; 



Plymouth, Falmouth, Isle of Skye {Rev. A. M. Norman) ; Northumberland and Durham coasts, 



25-46 fathoms, Preston Pans (oyster-ooze), Galway Bay, Roundstone Bay, Devonshire coast, South 

 Wales (G.S.B.). , 



The female of E. declivis seems to be very much more abundant than the male ; 

 indeed, except two specimens (figs. 54, 55) obtained by Mr. Norman from the Sound 

 of Skye, I have seen no males ; and these I conclude to be so simply from their close 

 agreement with Sara's description and with a drawing which he has kindly sent me. 

 I had been disposed (lacking the opportunity of anatomical investigation) to consider 

 the form figured at 49 to be the male of declivis ; but, in deference to the observations of 

 (x. O. Sars, I must for the present refer it to the following species. There is, however, 

 a curiously contorted form which occurs pretty numerously (figs. 52, 53) in a gathering 

 irom the Devonshire coast, and which, from its general resemblance, I am inclined to 

 refer to the present species. The bulk of the gathering consists of the ordinary female 

 onus (tig. 22); and there are none answering to the male, unless we consider as such th< 

 euned forms here referred to. Without further opportunities of investigation it is 

 impossible to decide the question. Possibly this curved form may be a distinct species ; 

 at we same time it may be well to bear in mind the possibility of there being two distinct 



