Tate — List of Irish Liassic Fossils. 21 



1 have no hesitation in referring the specimens named by D'Orbigny as 

 above, and which I have examined, to M. scabra of Terquem & Piette, which 

 I suspect is only the adult state of M. psilonoti. However, the Antrim shell 

 agrees better with the latter. The species was known to Portlock, in whose 

 collection it is labelled Modiola, nov. spec. 



22. Astarte Gueuxii, D'Orbigny, Prodromus, Vol. I. p. 216(1850). 



A. consobrina, Chapuis & Dewalque, Foss. du. Luxembourg, t. 22, 

 fig- 3, P- 49 (1853). 



A. complanata, et A. psilonoti, Quenstedt, Jura, t. 3, fig. 14 (1858). 



A. dentilabrum, Etheridge, Quart. Jour. Geol. Soc, Vol. xx., p. 

 113(1863). 

 This common Astarte I have compared with the type specimens of A. 

 Gueuxii, to which I unhesitatingly refer it. M. Terquem has named specimens 

 of A. dentilabrum, which I sent him, A. consobrina; so that the synonymic 

 terms may be considered well-established. Though D'Orbigny's name has 

 priority of publication, it has not been generally accepted, because of the sup- 

 posed incompleteness of the description, which runs thus : — " Species allied to 

 A. subtetragoua, Romer, but less carinated, less compressed, and costulated 

 only in the young state." 



Short as this diagnosis is, yet it is sufficient to its identification, and, conse- 

 quently, the specific name A. Gueuxii should be used. A. Eryx, of the same 

 author, is only a variety of this protean species ; and A. dentilabrum, Etheridge, 

 is founded on an aged form of the same species. The original description of 

 A. dentilabrian is as follows: — "Shell massive, ovate, and deep. Postero- 

 dorsal surface rounded, posterior end slightly truncate, about the position of 

 the annal adductor to the ventral margin ; anterior margin acutely rounded. 

 Umbones small, indistinct, subcentral, slightly curved anteriorly. Lunule 

 slightly excavated, small, oval, and attenuated, occupying half the area between 

 the umbo and the commencement of the antero-ventral margin. Border angu- 

 lar ; costse concentrically arranged, and coincident with the contour of the shell. 

 Ventral margin strongly denticulate. The whole of the teeth are inclined in- 

 wards, giving the edge of the shell a bevilled appearance — a marked feature 

 in the shell." 



23. Pholadomya Fraasii, Oppel, Juraformation, p. 95. 



The specific name here adopted was given by Oppel to a shell from the 

 Lower Lias, agreeing in form with P. ambigua, Ziet. , (P. glabra, Kg. ), but 

 possessing from 9 to 12 rather strong ribs, coarsely wrinkled concentrically. 

 Quenstedt has described the same species in much the same words with the 

 name P. prima, which, by the way, is a misnomer, inasmuch as the genus 

 dates farther back than the Lower Lias, and other species besides occur in the 

 lowest beds of the Lias. 



