LIMA. .) 



Anterior ears triaiio-ular, ratlicr small : jinstcrioi- cai's obtusely triaii^iilai', eloiio-ato, 

 with radial ribs. 



Valves ornamented with numerous flattened ril)s arranged on eithei' side ol' a 

 line passing from the umbo to the ventral margin, fi'om which they diverge sliglitly. 

 The ribs are nearly straight or sliglitly undulating, but are often bent abruptly 

 where they cross growth-lines. Surface of ribs nearly smooth, l)ut sometimes 

 showing very fine concentric ridges or (when worn) ojjlique stria\ On the inner 

 edge of each rib — that facing the middle line — there arc short, slit-like indentations, 

 above each of which a short spiny projection is seen in perfectly preserved 

 specimens. These slits and spines do not, as a rule, show a concentric arrange- 

 ment. The grooves separating the ribs are very narrow and are mnvked with 

 pits near the umbo and with transverse grooves ventrally. Sometimes near tlie 

 margins of the valves new ribs are intercalated or old ones bifurcate. 



Measurements : 



(1,2, 3, 7) Totterulioe Stone, Burwell. 



(4) „ „ Cherry Hinton. 



(.5, 6) Chalk Marl, Folkestone. 



Affiuifies. — The Seuonian form figured as Liimt aspcra by Goldfuss, Reuss, and 

 Fritsch is clearly distinguished from this species by the chevron-like ornamentation 

 on the ribs. Pictet and Campiche suggest that Goldfuss' species may be identical 

 with Liu)ii Pin/l-cri, Hagenow,' from Riigen, ])ut this view is not supported by the" 

 figures given by Vogel and Ravn. The form figured by d'Orbigny has a larger 

 apical angle than L. nspera, Mautell, and does not show the spiny projections on 

 one side of the i'il)S. 



The example figured by Reuss" as TAiiki lilana is similai' in form to T,. (iKjtero, 

 Mantell, Init does not appear to possess the spiiiy projections on the ril)s. 



Tijpi's. — I have not been able to find the tyjies.'* They came from the ("halk 

 Marl of Harasey and Stoncham. 



DisfriliHtian. — Chloritic Marl of Kastbout uc. Chalk Marl of Folkestone, and 

 Blue Bell Hill (Bui-ham). 'i'ottei-ulioe Stone of Arlesey, Burwell, Cherry liinton. 

 and Stoke Ferry. 



' 'Neues Jalirb. ftir Mm.,' etc. (1842), p. 55G. 



- 'Verstein. bohmisch. Krcidcformat.' (184r)), p. 35, pi. xxxviii, fi<if. 20. 



•'' Tlie name nnjM'ra was used by Chonuiity, (1784) for a recent species of Lima, Init since tliat has 

 been sliown to be a synonym of Lima scahra (Born, 1780) there does not appear to be sufficient reason 

 for 1,'iviii^' a new niuiic tn tin- Cli:ill< species whicli. for over oiLjhty years, ha.s Won known as T,imn 

 asjx'i'". Mantelt 



