306 Mr. J. E. Gray on Philippics Zoological Notices. 



7. Pandora striata, Dirt. Hist. Not. xxv. 



8. Pandorina? equivalvis Philippi, Sicul. xviii. t. 1. f. 11. a.b.c. 

 Pandorina coruscans, Scacchi, Sp. Zool. 14. Costa. 



There is a second species very nearly allied to it, but which 

 differs in being much narrower and longer in proportion. Ly- 

 onsia is the oldest published name for the genus; Magdala 

 was the name that Dr. Leach first gave to it in his MSS., but 

 he afterwards used Lyonsia. Brown, not satisfied with adopt- 

 ing Dr. Leaclr's earlier manuscript name, instead of Lyonsia, 

 has also added a new one, viz. Myatella. The shelly plate 

 which is found in the hinge of this genus in the most perfect 

 state of development, wa-, I believe, first described and figured 

 by Mr. Wood in his Conchology. This plate is peculiar to a 

 group of genera, which I think for several reasons, especially 

 on account of the general structure of the animals, should be 

 formed into a family separate from the Myadce. This family 

 contains the following genera : — 



Anatina=Auriscalpium, Schum. 



Cochlodesma=Anatina, §. 2. Turton. 



Periploma, ScAtfm. = Osteodesma (part) Desk. 



Thracia=Odoncinetus, Costa. 



Lyonsia — Magdala and. Myatella, Brown = Osteodesma (part) 

 Z)esA. = Pandorina, Scacchi. 



Myadora, G?-ay.= Pandora (species) Sower by.= A natina, Stutch- 

 bury, for Pandora brevis, Sow. 



Chamostrea, Roissy. = Cleidotherus Stutchbury, not Sower by, as 

 quoted by Dr. Philippi. 



Myochama, Stutchbury, and probably Cardilia, Desh.=zHem\cy- 

 clonosta, Desk. 



I described the animal of this genus in the first number of 

 my f Spicilegia Zoologica/ when describing Lyonsia cuneata. 

 The species of the different genera of Anatinidas pass very gra- 

 dually into each other, and I do not think that Lyonsia has 

 any affinity to either Pandora, Solenomya or Galeomma, the 

 latter having many characters in common with Gastrochcena, 

 Lyonsia has the piece in the hinge both in the young and 

 adult state ; and it may be remarked, that all bivalve shells, 

 Pandora as well as the rest, have both a ligament and a car- 

 tilage, which is often called a double ligament. 



