MALACOZOA. CErHALOPODA. FOEAMINIFERA. 321 



Shell rather hroadly oblong, suhtrimcate at tlie base, 

 rounded at the apex, nnich compressed, sloping to the mar- 

 gins, which are tliin and subcariuate ; of about sixteen alter- 

 nating cellules, disposed in two series, and horizontal, unless 

 at the commencement or apex, where they are vertical or ra- 

 diating ; their surface convex, strongly granulate, and glisten- 

 ing ; the colour reddish- white. Length nearly half a twelfth 

 of an inch, breadth rather more than half the length. 



Found by me, in December, 1842, among shell sand from 

 Cruden Bay, sent by Mr. Alexander Murray. 



FAillLY III. VaGINULINA. 



Shell many-celled, witli the cells disposed in a single 

 series, so as to present an elongated form, with the axis 

 gently curved. Name from the genus A'^aginula. Sti- 

 chdstega, D'Orbigny. 



Genus 1. Dentalina. P. 26, 40. 

 2. Dentalina Davidsonii. Davidsori s Dentaline. 



Shell subarcuate, considerably tapering, somewhat 

 compressed, marked in its whole length with longitudi- 

 nal crenulated furrows, and convex frosted ridges, of 

 twelve somewhat oblique cells, the last much larger, 

 with a small circular aperture ; the colour hyaline. 

 Named after Mr. Alexander Davidson. 



Shell elongated, very slightly bent, somewhat compressed, 

 tapering considerably toward the lower end, which is rounded, 

 and longitudinally grooved in its whole length ; the grooves 

 crenulated by transverse striulae, and the convex ridges frosted, 

 or very minutely granulated; of twelve flattened, transparent, 

 slightly oblique cells ; the last or uppermost cell much larger, 

 ovate, oblique, with a small circidar aperture, having a thick- 

 ened margin, and directed somewhat toward the concave side 

 of the shell ; the colour hyaline-white. Length two-twelfths 

 of an inch, greatest diameter a fifth of the length. 



In one specimen the dissepiments are brownish-red. 



Very nearly allied to Dentalina linearis, from which it dif- 

 fers chiefly in having the grooves and ridges, which are not 

 oblique, crenulated, and extending over its whole length, ex- 

 cepting the last cell, which also differs in form. Supposing it 



