Mr. A. Adams on a new species of Macgillivrayia. 373 



or rather angularly produced behind ; margin crenulated. Pe- 

 riostraca velvety. 



a. Shell smoothj ventricose ; hinder slope rather angular. A. vio- 



lascens. 



b. Shell smooth y rounded behind; periostraca velvety, A. pilosa, 



A. Glycimeris. 



c. Shell smooth, rather angularly produced behind. A. penna- 



ceus, A. angulatus, A. longior, A. obliquus. 



d. Shell subcostafe, rather angularly produced behind. A. radiatus. 



e. Shell subcostale, short behind. A. ovatus, A. laticostatus. 



f. Shell radiately ribbed, slightly truncate behind. A. pectini- 



formis. 



g. Shell irregularly ribbed and radiately striate. A. insequalis. 



II. Cardinal area small, with a smaller triangular central impres- 

 sion for the cartilage (like the cartilage-pit of Lima) just 

 under the umbo and above the division between the teeth. 



14. Limopsis, Shell circular, compressed, solid, radiately 

 striate. Periostraca ? L. multistriatus. 



15. Limcea. Shell ovate, obliquely produced behind. Peri- 

 ostraca hairy. L. pygmcea = Limcea Sarsii, Loven. L. ? 



(Belcher). 



The fossil Limaa scalaris, of Barton Cliff, is somewhat inter- 

 mediate in form between these two genera. 



XXVIII. — On a New Species of Macgillivrayia. By Arthur 

 Adams, S.R.N., F.L.S. &c. 



To the Editors of the Annals of Natural History. 



On the Line, January 7, 185/. 

 Gentlemen, 



I have the pleasure of sending you a notice of a new Macgilli- 

 vrayia, the same species alluded to in p. 89, vol. ii. of the ^Ge- 

 nera of Recent Mollusca,^ but there erroneously referred to the 

 genus Calcarella. Associated with my M. echinata were exam- 

 ples oi Brownia, another small genus of pelagian MoUusks, first 

 named by D^Orbigny, and called afterwards Echinospira by 

 Krohn, Calcarella by Souleyet, and Jasonilla by Macdonald, the 

 animal of which was not observed. An example, likewise, of a 



