184 SALENIA 



" Les nombreux materiaux que nous avons sous les yeux, et que nous venons de com- 

 parer, nous engagent aujourd'hui a revenir sur cette opinion. Associes aux types les 

 mieux caracterises il se rencontre des exemplaires chez lesquels les differences que nous 

 venons d'enumerer s'effacent plus ou moins, et qui tendent a se rapprocher, par des 

 passages insensibles, du veritable S. scutigera. Les uns, tout en conservant leur grande 

 taille, sont moins renfles, garnis de tubercules moins abondants, et presentent un appareil 

 apicial plus developpe, plus epuis et arrondi au pourtour ; les autres, plus petits, ont un 

 appareil apicial qui cesse peu a peu d'etre pentagonal, et tend, en s'agrandissant a s'ar- 

 rondir sur les bords. lis appartiennent encore a la variete geometrica ; cependant ils 

 offrent une grande ressemblance avec les exemplaires Cenomaniens ; quelquefois meme il 

 est difficile de les en separer. 



" Woodward, d'apres Forbes, decrit sous le nom de S. Portlockii une espece d'assez 

 grande taille, elevee, sub-globuleuse, a ambulacres etroits et sinueux, a disque apicial 

 mediocrement developpe ; ses caracteres la rapprochent beaucoup du S. scutigera, var. 

 geometrica. Peut-etre devrait-elle y etre reunie." 



Locality and Stratigraphical Position. — This fine large species occurs in the Upper 

 Chalk of the North of Ireland, where it was collected by the officers of the Geological 

 Survey, and figured in Colonel Portlock's ' Report on the Geology of the County of 

 Londonderry.' It is found very rarely in the upper beds of white Chalk at Norwich and 

 in Sussex, and flint moulds are not uncommon in the Gravel of Norfolk. The specimens 

 figured belong to the British Museum. Mr. Searles Wood possesses a good example, and 

 Mr. John King, of Norwich, has a large one which measures eleven lines in height and 

 as much in diameter. There is also a fine specimen in the Hunterian Collection, Museum 

 of the College of Surgeons (Woodward). 



Salenia magnifica, Wright, nov. sp. PI. XLIV, fig. 1, a — /. 



Diagnosis. — Test spheroidal, much elevated ; ambulacra nearly straight, two marginal 

 rows of large mammillated and two internal rows of smaller granules; poriferous zones 

 narrow, pores very oblique and unigeminal ; inter-ambulacra wide, two rows of tubercles, 

 seven in each, the ambital and dorsal very large, the basal very small ; miliary zone wide, 

 and sparsely covered with granulations ; apical disc large, plates smooth, sutures punc- 

 tuated, vent large, oblong ; periprocte hexagonal, elevated, and projecting ; mouth-opening 

 small, oblong. 



Dimensions. — Altitude, nine lines ; latitude, ten and a half lines. 



Description. — This magnificent Salenia from the White Chalk belongs to the British 

 Museum, and to the illustration of its finely preserved details I have devoted PI. XLIV. 

 The test is spheroidal and much elevated, its altitude exceeding its diameter by one and a half 

 lines ; the ambulacral areas are narrow and slightly flexed, with two marginal rows of large 



