637 



BRACHIOPODA. 



BRACHIOPODA. 



633 



of Anomia on the organisation of one of the Tereblaiulce which he 

 included in that genus." 



The recent species are numerous and widely diffused, and the genus 

 appears to be capable of flourishing in extremely warm and extremely 

 cold regions, as well as in more temperate climates. Thus some of 

 the species have been found in. the Indian seas and at Java (T. flaves- 

 cew, Lam., for example), and T. psittacea, brought home from the late 

 expedition by Captain James Ross, R.N., was fished up from a depth 

 of twenty-two fathoms near Felix Harbour, in lat. 70 N., on the east 

 side of Boothia. The average depth at which Terebratula has been 

 found ranges from ten to ninety fathoms. De Blainville has thus 

 subdivided the species : 



A. Summit of the larger valve pierced with a round hole, well defined. 



1. Valves triangular, with a straight anterior border. 

 Example, Terebratula, digona (fossil). 



Terebratula digona. 



2. Valves rounded at their anterior border. 

 Example, Terebratula ylobasa (recent). 



Terebratula globota. 



3. Valves rained as it were, or hollowed on the mesial line. 

 Examples, Terebratula lanyuirua, and Terebra'.ula dorsata (recent). 



Terebratula donata. Internal views. 



Bilobated, the valves striated from the summit to the circumference 



and deformed as it were at the junction of their border 

 Example, Terebratula dfformit (fossil). 



Terebratiil 



5. Trilobated as it were by the projection of the mesial part. 

 Example, Terebratula alata (fossil). 



Terebratula alata. 



B. The heel of the larger valve deeply notched up to the border of 

 articulation ; notch or fissure rounded. 



1. Valves rounded at their anterior border. 

 Example, Terebratula rubra, (recent). 



Tcre'jratiila rubra. 



2. Valves sub-bilobated by the depression or emargiiintion, which in 



apparent at the anterior border. 

 Example, Terebratula Ciit Serprnlit (recent). 



Terebratula Caput Serpentis. 



C. The opening of the heel of the larger valve, marginal, triangular, 

 and elongated. 



1. Valves rounded. 

 Example, Terebratula Lyra (fossil). 



Terebratula Lyra, a, Front view ; l>, side view. 



2. The valves sub-bilobated. 

 Example, Terebratula canalifera (fossil). 



Terebratula canalifera. 



3. The valves rounded ; a mesial partition (doiaon) in the larger 

 valve, placed between two in the smaller, so as to give in the cast 

 the representation of five distinct pieces, three for one valve and 

 two for the other. 



Genus Pentottera, Sowerby. Fossil. 



D. Opening of the heel marginal, triangular, but much larger trans- 

 versely than longitudinally. Line of articulation quite straight. 

 1. The small valve provided in its mesial portion with a straight 

 flattened support, bifurcated at its free extremity ; a partition 

 (chiton) in the other valve penetrating into this bifurcation. 



Genus <SV )//</'"' /'/'"'*> IVI'rance. Fossil. 

 Example, Stryyoccp/iuius Bur/ini. 



