DR. T. DAVIDSON ON RECENT BRACHIOPODA. 59 



33. Waldheimia floridana, Pourtales. (Plate XII. ligs. 1-.5.) 



Waldheimia floridana, Pourtales, Bull. Mus. Comp. Zool. Harvard, vol. i. p. 127, 1868; Dall, Bull. 

 Mus. Comp. Zool. Harvard, vol. iii. p. 12, pi. i. figs. 1-3, 18"1. 



Eudesia floridana, Bull. Mus. Comp. Zoiil. arvard, vol. ix. p. 103, 1881. 



Shell trians:^ular, widest anteriorly, tapering posteriorly, generally as wide or wider 

 than long ; anterior margins strongly flexuous. Dorsal valve uniformly convex poste- 

 riorly, anteriorly divided into three lobes, the central by far the largest, forming a 

 wide moderately elevated fold ; lateral edges of valves flexuous, anterior corners rounded. 

 Ventral valve deeper than the dorsal one, with a large wide mesial sinus commencing at 

 a little distance from the extremity of the beak and gradually widening as it I'eaches the 

 front ; lateral lobes nearly flat or gently concave, sloping rapidly from tlie outer side of 

 the fold and sinus to the edsjes of the shell. Beak incurved and truncated by a small 

 circular foramen, very little separated from the hinge-line by a narrow deltidium in two 

 pieces ; beak-ridges rounded. Surface smooth. Colour greyish or brownish white with 

 a slight touch of yellow. Length 11, width 12, depth 8 lines. 



In the interior of the doi'sal valve the cardinal process is small, the hinge-plate rather 

 large, and from under its base a mesial septum of small elevation extends to about two 

 thirds of tlie length of the valve. Loop simple, very broad and separate anteriorly, 

 narrow posteriorly. Stomach spherical, with a long cylindrical intestine. 



Uah. Very abundant, attached to Plorida Reefs, depth 100 to 200 fathoms, on rocky 

 1)ottom (Pourtales) ; off Sand Key, 125 fathoms (Sigsbee) ; off Havana, 175 fathoms 

 (Dall). 



Obs. Thanks to the great liberality of Prof. A. Agassiz, I have been able to examine a 

 large number of specimens of this remarkable and Avell-characterized species from the 

 dimensions of five up to eleven lines in length. When quite young and up to a some- 

 what advanced period of its growth, the shell is longer than wide, the fold and sinus 

 being scarcely indicated in very young examples. Dall, in his excellent description of 

 this species, states that it belongs to a peculiar group including W. Jloridana, W. septigera, 

 and W.BaphaeUs; he adds : — "Thus it is seen that the smallest species [^F.j'^orJdrtP/rt] is 

 by far the widest and most inflated proportionately ; the second species is the flattest 

 in proportion to its length ; and the third the most elongated." 



" The greater portion of the mantle of W. Jioridana is of the most extreme tenuity and 

 perfect transparency. It is furthermore so closely attached to the shell as to render its 

 removal intact — even with the aid of acid— a matter of great difficulty. With this excep- 

 tion, the examination of its anatomy is easy The soft parts are mostly of a translucent 



whitish color. The number and disposition of the muscles are similar to those of W. mis- 

 tralis, already described by various authors. The muscles themselves are of a glistening 

 tendinous appearance, except at their points of attachment, where they are of a more or 

 less dark yellowish-brown. The peduncle is moderately long, and the portion which is 

 external or contained in the foramen is covered with a dark, horny, reddish-brown 

 membrane or skin, and the attached extremity is trumpet-shaped. Upon opening the 

 shell in its normal position, the median spires of the brachia are seen to be somewhat 

 widely separated, and between them is stretclied a flne translucent membrane extending 



S* 



