34-2 GENERAL SUMMARY TO 



Tretenterata, King. 

 Lingula anatina, Lam. 1819. Glottidia Palmieri, T)all. 1871. 



— exusta, Reeve. 1861. — albida, Hinds. 1844. 



— hians, Swainson. 1823. — pyramidata, Stimpson. 1860. 



— hirundo, Reeve. 1861. Crania anomala, Muller. 1776. 



— jaspidea, Adams. 1863. — — var. alba, Jeffreys. 1869. 



* — lepidula, Adams. 1863. — — var. Pourtalesi, Dull. 1871- 



— Reevei (ovalis), Dav. 1880. — japonica, Adams. 1863. 



* — ■ smaragdina, Adams. 1863. — Suessi, Reeve. 1862. 



* — Adamsi, Dall. 1873. Discina striata, Schumacher. 1817. 



— tumidula, Reeve. 1841. Discinisca lamellosa, Broderip. 1833. 



* — Murphiaua, King. 1861. — laevis, Sow. 1822. 



* — affinis, Hancock. 1858. — Cumingi, Broderip. 1833. 

 Glottidia antillarum, Reeve. 1861. — atlantica, King. 1868. 



— Audebardi, Brodrip. 1833. * — tenuis, Sow. 1847. 



* — semen, Broderip. 1833. 



Several monographs and many papers have been published on the Recent Brachio- 

 poda, but those by G. Sowerby 1 and L. Reeve 2 contain the larger number of species, and 

 their figures are very good. Reference to the other works and papers on the subject will 

 be found in the Brachiopod Bibliography. 3 



It resulted from my examination of the Brachiopoda dredged by the " Challenger " 

 Expedition that animals of the same species are capable of existing at different depths 

 without any observable modification in shape or character. 



The ranges in depth noted in the list published in the " Challenger " Report and from 

 other sources are even now sufficient to warrant us in arriving at certain general induc- 

 tions. Thus, for sake of argument (for all we can say on the subject must necessarily 

 be provisional), suppose we put down the number of recorded recent species, and named 

 varieties, at 135, that is to say 125 species and 10 named varieties, a number that will 

 certainly have to be largely reduced, or say 107, as nothing is known respecting the ranges 

 of 25 or 26 so-called species. 



From the shore to 500 fathoms there are some 98 species or named varieties; 12 of 

 these ranging up to 100 fathoms or less. 



From 501 to 1000 fathoms some 16 species. Of these only one, Discina atlantica, 

 ranges from 690 to 2400 fathoms. 



From 1001 to 1500 fathoms some 6 species. Of these Terebratula Wyvillei ranges 

 from 1035 to 2900 fathoms, the greatest depth at which any species has been found. 



1 The 'Thesaurus Conchyliorum,' 1846, parts vi and vii. 



2 Monographs of the genera Lingula, Orbicula, and Terebratula, 'Conch. Icon.,' 1860 — 1862. 

 Chemnitz in 1785, ' Neues systematisches Koncliylien-Kabinet,' vol. viii, described and figured a number of 

 recent Brachiopoda, but his illustrations do not equal those of Sowerby and Reeve. 



3 British recent Brachiopoda have been minutely described and illustrated by Forbes and Hanley in 

 their work on 'British Mollusca' in 1849, and by Dr. Gwyn Jeffreys in volumes 2 and 5 of his 'British 

 Conchology,' 1863 and 1869. 



