Dr. Philippi on the Animal 0/ Astarte incrassata. 29? 



Plate IV. Fig. 1. Pandorina coruscans, Scac, a small specimen, lying upon 



the left, more strongly vaulted, shell. 

 Fig. 2. The same lying on the ventral side in order to show the area 



and lunula. 

 Fig. 3. The same opened and twice magnified. 



a. The little hone in the ligament. 



b. The cavity into which the bone fits. 



c. The external ligament. 



Fig. 4. 'J'he animal of Pandorina after a drawing of Sr. Scacchi. 

 Fig. 5. A shell of Pandora rostrata for comparison. 



a. An external ligament? 



h. The internal ligament. 



c. The hinge tooth. 



7. On the Animal of Astarte incrassata, De la Jonk. 



Plate IV. fig. 6. 



I obtained two specimens of this rare animal which w^ere 

 still alive, but as they would not open their shells I was com- 

 pelled to use force. The animal was therefore seen in a half 

 contracted state : the mantle is almost entirely split : a nar- 

 row band separates posteriorly a small roundish aperture, 

 which supplies the place of the anal and branchial tubes, as 

 was to be expected from the analogy of the shell with that of 

 the genus Venus, At the margin of this aperture, as well as 

 at the margin of the hinder portion of the front aperture, the 

 mantle is of a dark brow n colour and beset with very delicate 

 white fiUform cirri. More anteriorly these cirri become smaller 

 and take in some degree the shape of white folds. The /bo/ is 

 securiform, acute behind and in front, therefore constricted, 

 and in this way distinctly separated from the mass of the in- 

 testines ; it is of a scarlet red colour. The branchice are dissi- 

 milar ; the interior one is nearly triangular, and exhibits a 

 dorsal, a ventral, and a front side. It is connected by the 

 dorsal side to the outer branchia, which is only about half the 

 size, not projecting so far anteriorly, and is rounded where the 

 inner one exhibits the strongly projecting angle. Both the 

 branchiae are fastened by their common apex to the narrow 

 connexion of the two lobes of the mantle between its anterior 

 and posterior aperture, yet so slightly, that they are easily 

 separated. The appendices buccales are two in number on each 

 side, small and oblong. 



Sr. Scacchi observed this animal some years ago, and gave 



