About 25 fossil species are known, commencing with the 

 Eocene. Conrad's genera Pyramitra, Caelatura and Terebri- 

 fusus, referred by him to Terebridse, are not members of the 



group* 



The geographical distribution of Terebra is tropical and sub- 

 tropical, and the species appear to be inhabitants of shallow 

 water principally ; indeed, none have occurred, so far, at great 

 depths. 



Gray, in 1834 (Zool. Proceedings, 59), enumerates 42 species, 

 excluding those subsequently referred to Bullia ; half of these 

 were first described in his paper. He thus groups them : 



I. Whorls with a posterior spiral sulcus, inner lip thin, con- 

 cave. 30 species. 



II. Whorls with posterior spiral sulcus, inner lip thickened, 

 subelevated. 7 species. 



III. Whorls without posterior sulcus. 5 species. 



Kiener's monograph in his " Coquilles vivantes," contains 35 

 species. 



Hinds described many species in the Zoological Proceedings 

 for 1843, and he monographed the genus in Sowerby's Thesaurus 

 Conchyliorum (i, p. 141 bis to 190, PI. 41 to 45) ; enumerating 

 and figuring 109 species. 



Hinds remarks that " The only sectional division of the genus 

 that has been attempted, is that of Mr. Gray in the above Pro- 

 ceedings. This division is three-fold ; the two first of these 

 depend on the presence of the peculiar girdling or division of 

 the whorls, and which is very conspicuous in many species, but 

 practically I fail to carry it out in detail. Some species also 

 are so excessively variable in this character, that M. Kiener has 

 described T. castanea as having girdled whorls, but has figured 

 it without them. The latter writer has not attempted any 

 grouping of the species in his monograph, and as he has done so 

 in most cases, we may venture to infer that he did not see room 

 for it here. 



" It cannot be denied that among the numerous species are 

 several shells which, taken by themselves, would furnish good 

 grounds for sectional or even subgeneric divisions. And if we 

 take T. maculata as the proper generic type, then T. lanceata, 



