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II. A Monograph of Hecent BracMopoda.—Vavt II. 

 i?y Thomas Davidson, LL.D., F.ll.S., F.L.S., F.G.S., §-c. 



Read 3rd June, 1886. 



(Plates XIV.-XXV.) 

 Subfamily Tekebeatellin^. 



Genus TEEEBEATELLA, d'Orbigny, 1847. 



In this genus Alcide d'Orbigny proposed to include all those species in which the long 

 reflected loop has its principal stems twice attached : — first by their crura to the base of 

 the hinge-plate, and again by horizontal laminae given off from about the middle of the 

 principal stems, which afterwards become attached to the anterior extremity of a low 

 mesial septum. The Terebratula dorsata of Gmelin was selected as the type. 



In 1870 Mr. Dall proposed to separate from Terebratella, as thus defined, those forms in 

 which the reflected portions united form a loop, and in which the mesial septum is very 

 large, elevated, and projects beyond the anterior extremities of the loop. Ty^pe Mar/asella 

 Jiexiiosa, P. King. 



It has been ascertained that great changes take place in the form of the loop of Tere 

 bratella during the progress of its development from the young to the adult condition 

 and that when young, and up to a certain age, it shows the loop and septum of Magasella 

 Indeed Mr. Dall has frankly admitted to me that some of the species referred to Maga 

 sella are immature forms of Terebratella ; but for some others, such as Magasella flexuosa, 

 P. King, Magasella siiffusa. Peeve, which retain the Magasella loop and septum in their 

 adult condition, he proposes to retain the subgenus Magasella. 



We have recognized nine species of Terebratella and three uncertain ones, viz. : — 



1. Terebrntella dorsata, Gmelin. 



2. transversa, Vt. B. Sowerby. 



G. Terebratella rubicunda, G. B. Sowerby. 



7. frontalis, MiddendoriF. 



8. cruenta, Dillwyn. 



9. Marue, Adams. 



3. corcanira, Adams & Reeve. 



4. liluiifordi, Diiiikcr. 



5. spUzbergensis, Davidson. 



The uncertain species are Terebratella putvinata, Gould ; Terebratella rubiginosa, Dall , Terebratella 

 Frielii, Davidson. 



The very numerous synonyms have been added to the descriptions of the species. 

 37. Terebratella dorsata, Gmelin, sp. (Plate XIV. figs. 9-19.) 



Anomie Magellanique striee, Davila, Catalogue Systematiciue dcs Curiosites dc la Nature, vol. i. p. 312, 

 pi. XX. fig. A, 17G7. 



? magellanique, Walchs, Naturforseher, p. 202, pi. iii. figs. 3, 4, 1774. 



? magellanique, Favanne de Monteervcllc, Conebyliologie, pi. xli. fig. A. 3, 1780. 



SECOND SERIES. — ZOOLOGY, VOL. IV. 11 



