10 Mr. T. Davidson on the Brachiopoda of the Maltese Islands. 



Maltese Fossils " (Proc. Geol. Soc. vol. iv. No. 97), and appended 

 to Capt. Spratt's memoir on the geology of the island. 



A. decoUata is also common in the middle and upper Miocene 

 beds of Piedmont and Tuscany, but is rare m the Pliocene of 

 Sienna ; it occurs in the Pleistocene beds of Messina. 



6. Thecidium Adamsi, Macdonald. PI. I. fig. 13. 

 Thecidium Adamsi, J. D. Macdonald, Quart. Journ. Geol. Soc. vol. xix. 



p. 517 (1863) ; Davidson in Longman's Geol. Mag. for July 1864. 



As this interesting little species has been recently correctly 

 described and figured in detail by myself in * Longman's Maga- 

 zine,' all we need now repeat is that the shell occurs in great 

 abundance in the upper portion of the " Lower Limestone" (5), 

 and it is usually associated with Orbituides, Cidaris, Echinus, 

 Scutella, and other forms characteristic of the situation, and 

 apparently never found in any of the superincumbent beds. 



7. Rhynchonella hipartita, Brocchi, sp. PI. I. fig. 14. 

 Anomia bipartita, Brocchi, Conchiologia Fossile, vol. ii. p. 466, pi. 10. 



fig. 7 (1814). 

 T , Def. Diet. Sci. pp. 156, 182; Philippi, Enumeratio MoUus- 



corum Sicilise, vol. ii. tab. 18. fig. 5. 

 Terebratula incurva. Von Buch, Ueber Terebrateln, tab. 2. fig. 40 (1834). 



Sp. char. Shell of a somewhat globosely triangular shape, 

 generally rather wider than long, while at times the length 

 slightly exceeds the width. Dorsal valve deeper and much more 

 convex than the opposite one; mesial fold wide and apparent 

 only towards the front. Ventral valve moderately convex, with 

 a wide, square-shaped, shallow sinus beginning towards the 

 middle of the valve and extending to the front. Beak acuminate, 

 acute, incurved, leaning considerably over the umbo, with an 

 elongated foramen extending from under the extremity of the 

 beak to the umbo, and almost entirely surrounded by a delti- 

 dium. The surface is usually smooth, but on some specimens 

 a few short ribs appear towards the frontal and lateral margins, 

 while concentric lines of growth cover the surface. Length and 

 breadth about equal. One Maltese specimen measured 10 lines 

 in length and breadth, 7 in depth ; but it attains larger propor- 

 tions in other localities. 



Obs. This very variable shell is stated by Dr. Adams to be 

 common enough, along with Megerlia truncata and Argiope de- 

 coUata, in the "Upper Limestone" (1), but is difficult to obtain 

 entire. In Italy it occurs abundantly in the upper Miocene 

 and Pliocene of Tuscany. In the island of Sicily it is common 

 in the Miocene of Palermo ; but, according to Prof. Sequenza, 

 is less abundant in that of Messina. 



