REPORT ON THE LAMELLIBRANCHIATA. 321 



side is rather higher up than iu front. Tlie (hn-sal margin is straightish on each side the 

 beaks, which are small, slightly prominent, and rather excentric. Tlie hinge is slight, 

 and armed with about six teeth on each side the small ligament-pit. The interior is 

 bluish-white. 



Length 3f mm., height 2^, diameter 1^. 



Habitat. — Station 244, Mid North Pacific Ocean, in 2900 fathoms. 



Leda Jeffrey si, Hidalgo, is the Atlantie analogue of this species. 



Area {Barbatia?) imitata, n. sp. 



Testa forma habituque Arcce frielei simillima, agquivalvis, oblique rotuudata, sub- 

 globosa, inseqnilateralis, albida, epidermide tenui pilosa pallide fuscescente induta. Valv£e 

 tenues, liris tenuibus radiantibus aliisque conceutricis paulo minus conspicuis can- 

 cellatse. 



Length 3f mm., height 3, diameter 2 J. ' 



Var. ; Testa magis elongata. 



Length 4^ mm., height 3^, diameter 2g. 



Habitat. — Station 244, Mid North Pacific Ocean, in 2900 fathoms. 



This interesting form belongs to a small group of species which bear a strong family 

 likeness to one another, namelj^, Area pectuncndoides, Area frielei, 

 Area incBquiscidpta, Area cidehrensis, and a few others. 



Area imitata differs from specimens of Area peetuneidoides of 

 similar size in being more coarsely clathrate and in having the 

 valves equal, whereas, in the latter species, the right is smaller 

 than the left. Area culebrensis is a more elongated shell than ' "" "'^ lo) »«> a «, n. sj.. 

 that under consideration, Area inoequiseidpta differs in having the 

 valves differently sculptured and of unequal size, and Area frielei 

 has rather finer sculpture and is somewhat different in outline. 

 The distinctions above mentioned are but slight, and based upon 

 very limited material, and, without comparison of the specimens, 



•; ... . , . Arca\BaTljatia)miiiata(\a.T.Y 



it is impossible to discriminate the different species. I have 



already recorded (p. 3) the existence of two all but identical species of the same genus 

 occurring at the above locality and at a great depth in the Atlantic. Here again is an 

 instance in which the genus Area has almost exactly simdar representatives in the two 

 oceans, at enormous depths. 



(ZOOL. CUAU.. E.\P. PART .XXXV. — ISS-".) J[lll 4 1 



