BRACHIOPODA 267 



quite recently have shown the relationship between the Brachiopoda and 

 Phoronis. The affinities of the Brachiopoda are thus still obscure, but 

 are undoubtedly with the Bryozoa and Phoronis. 



The subphylum contains 2 orders. 



Key to the orders of Brachiopoda : 



Qi Shell without a hinge joining the valves 1. Ecardines 



a. The valves of the shell joined by a hinge .2. Testicardines 



Order 1. ECARDINES. 



Shell horn-like or calcareous, the valves not being joined posteriorly by 

 a hinge but only by muscles; mantles also not joined; no calcareous arms 

 projecting from the dorsal valve to support the tentacular arms; anus 

 present: 3 families with about 32 living and 400 fossil species, most of 

 the latter being Paleozoic. 



Key to the families of Ecardines here described : 



tti Peduncle present ; animal living in sand 1. Lingulidae 



Co Peduncle not present; animal attached by ventral valve 2. Craniidae 



Family 1. LINGULIDAE. 



Shell more or less rectangular in shape, horn-like in texture, with 

 valves of equal size, truncated in front and pointed behind; peduncle con- 

 tractile and usually long; tentacular arms spiral, with about 6 whorls; 

 mantle very vascular, with long stiff setae on the edges: 16 species, in. 

 2 genera, of which Lingula is found in the Pacific and Indian Oceans and 

 Glottidia on both shores of America; 100 fossil species. 



Glottidia Dall. Shell smooth and linguiform; 

 dorsal valve with 2 internal, sliaip, incurved laminae 

 diverging from the beak and extending a third of the 

 length of the shell; ventral valve, with a mesial septum 

 extending forwards from the beak: about 4 species, on 

 both Atlantic and Pacific coasts of America. 



G. albida (Hinds). Shell narrow, oval, tapering ^.^ 4p^g_cuot- 

 at the beak, vei-y slightly curved in front, smooth, and ^'^%Vyon)"'^^ 

 white; peduncle stout and short, 45 mm. long; shell 30 

 mm. long: Pacific coast from San Diego to Monterey, from low-water 

 mark to 60 fathoms. 



G. audebarti* (Broderip) (Lingula pyramidata Stimpson) (Fig. 438). 

 Shell narrow, tapering at the back, front margin nearly straight; color 

 white, with transverse bands of green; peduncle very long and slender; 

 animal hermaphroditic; length of shell 27 mm., breadth 10 mm.; length 



* See "A study of the Structure of Lingula (Glottidia) pyramidata Stimp.," by 

 H. E. Beyer, Stud. Biol. Lab., Johns Hopk., Vol. 3, 1886. 



