112 DE. T. DAVIDSON ON EECENT BEACHIOPODA. 



64. Laqueus califoknicus, Koch, sp. (Plate XVIII. figs. 6-9.) 



Terebratula califonuca, Kocli, Kiister, nov. ed. Chemnitz, Couch. -Cabinet, vol. viii. pi. 2 b. figs. 21-23, 

 1843. 



Terebratula Kochi, Kiister, ibid. vol. viii. pi. 2d. figs. 1-3, 1843. 



Terebratula Ca/ifornica, G. B. Sowerby, Thes. Conch, i. p. 352, pi. Ixx. figs. 50-52, 1846. 



Terebratula Californiana, Davidson, Sketch of a Classification of Recent Brachiopoda, Ann. & Mag. 

 Nat. Hist. 2nd ser. vol. i.K. p. 3G4, 1852. 



Waldheimia Californica, Woodward & Gray, Cat. of Brach. in Brit. Mus. p. 60, 1853; V. Carpenter, 

 Rep. Brit. Assoc. 1856, p. 298; Cooper, Geogr. Cat. p. 3. no. 5. 



Waldheimia californiana, E. Suess, Ueber die Wohnsitze der Brach. Sitzungsb. k. Akad. der Wissensch. 

 Wien, Bd. xxxvii. p. 202, 1859. 



Terebratula [Waldheimia) globosa, L. Reeve (not of Lamarck), Icon. Conch. Monogr. Ter. pi. ii. fig. 3, 

 18C0. 



Laqueus californicus, Dall, Amer. Jouru. Conch, vol. vi. p. 123, 1870, L. Californica, Proc. Acad. Sci. 

 Philadelphia, 1873, p. 186 ; E. E. Deslongchani])s, Etudes critiques sur des Brachiopodes nouveaux ou 

 l^eu connus, p. 202, 1884; Zittel, Handbuch der Palaontologie, p. 706, 1880. 



Shell large, longitudinally oval, inflated ; margins slightly sinuous. Dorsal valve uni- 

 formly convex, with occasionally a very slight tendency to depression close to the frontal 

 margin. Ventral valve a little deeper than the dorsal one, with sometimes a slight indi- 

 cation of a mesial longitudinal elevation or flattened fold ; beak incurved, truncated by 

 a small circular foramen, margined anteriorly by two wide deltidial plates ; beak-ridges 

 sharply defined, leaving between them and the hinge-line a flattened space. Surface of 

 valves smooth, with concentric lines of growth, shell-perforations rather large. Colour 

 livid yellowish brown or light reddish brown. Length 2 inches 6 lines ; breadth 1 inch 

 11 lines ; depth 1 iucli. In the interior of the dorsal valve the hinge-plate is bifid ; car- 

 dinal process inconspicuous. The septum, of small elevation, extends from under the 

 middle of the hinge-plate to a little more than a third of the length of the shell ; the 

 principal lamella} of the loop, after having been attached to the angles of the hinge-plate 

 and giving off short curved crura, proceed a short distance, when they again give off two 

 slightly oblique laminte, which become attached to the anterior edge of the mesial septum. 

 The principal stems of the loop then extend to witliin a short distance of the frontal 

 margin, Avhcre they become deflected in the shape of a horse-shoe, giving ofi' on each side 

 a short lamella near their upper extremity, thus connecting the reflected portion with 

 the principal stems of the loop close to the point where the two oblique lamellte leave for 

 their attachment to the mesial septum. 



Ilah. Coast of Barbara County, California, in 90 fathoms (Dall). 



Ohs. This fine species, little inferior in size to Waldheimia venosa, Solander, has 

 often been confovmded with it on account of its similarity in external shape. The two 

 species are, however, perfectly distinct. The small foramen, w^idely separated from the 

 hinge-plate in Laqueus californicus, at once distinguishes it from IP'uhlheimia venosa, 

 which possesses a much larger foramen but little separated from the hinge-line. The 

 absence of a defined cardinal process in the interior of the shell and a very different 

 arrangement of the loop further distinguish the two species. 



The Terebratula Kochi, Kiister, is only a smaller specimen of Laqueus californicus. 



