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



or rather angularly produced behind j margin crenulated. Pe- 

 riostraca velvety. 



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



lascens. 



b. Shell smooth, 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 subcostate, rather angularly produced behind. A. radiatus. 



e. Shell subcostate, 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-jnt 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. Limaa. Shell ovate, obliquely produced behind. Peri- 

 ostraca hairy. L. pygmcea ■=■ Limaa Sarsii, hoven. 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 1, 186/. 

 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 of Brownia, another small genus of pelagian Mollusks, 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 



