10 Mr.T. Davidson on the Brachiopoda of the Maltese Islands. 
Maltese Fossils” (Proc. Geol. Soe. vol. iv. No. 97), and appended 
to Capt. Spratt’s memoir on the geology of the island. 
A. decollata is also common in the middle and upper Miocene 
beds of Piedmont and Tuscany, but is rare in the Pliocene of 
Sienna; it occurs in the Pleistocene beds of Messina. 
6. Thecidium Adamsi, Macdonald. PI. I. fig. 18. 
Thecidium Adamsi, J. D. Macdonald, Quart. Journ. Geol. Soe. 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 Orbetoides, Cidaris, Echinus, 
Scutella, and other forms characteristic of the situation, and 
apparently never found in any of the superincumbent beds. 
7. Rhynchonella bipartita, Brocchi, sp. Pl. I. fig. 14. 
Anomia bipartita, Brocchi, Conchiologia Fossile, vol. ii. p. 466, pl. 10. 
fiz. 7 (1814). 
, Def. Dict. Sci. pp. 156, 182; Philippi, Enumeratio Mollus- 
corum Siciliz, vol. ii. tab. 18. fig. 5. 
Terebratula incurva, Vou Buch, Ueber Terebrateln, tab. 2. fig. 40 (1834). 
Sp. char. Shell of a somewhat globosely triangular shape, 
eenerally 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- 
collata, 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. 
