14 DK. T. DAVIDSON ON EECENT BRACHIOPODA. 



small and oval, tapering towards the intestine, which is nearly twice as long as the 

 oesophagus. 



" The heart in most specimens was pyriform and of a moderately large size. 



" The genitalia . . . are situated in a reticulated series of sinuses, on the surfaces of 

 the sides of the perivisceral tissues. 



" Ahove and behind the mouth, and directly in front of the anterior occlusor (retractor) 

 muscles, the external tissu.es of the perivisceral membrane are thickened, or a mass of 

 cellular tissue is interposed between the laminse of the membrane. 



" No peculiarities of note were observed in the shell-structure. The perforations appeared 

 to be slightly further apart than in T. vitrea, but the difference was not much greater 

 than that which may be observed in the shells of different individuals of the same species." 



Mr. Dall then describes what he believes to be the young of T. cuhensis, dredged off the 

 Samboes, on the Florida reefs, a minute, polished, liyaline shell, 4-lOOths of an inch in 

 length, and follows by describing the muscular system, brachia, and organs of digestion. 



.Liothyris sphenoidea and its synonym T. cuhensis appear to be very abundant in 

 their especial haunts. I have also been able to examine the animal from one of the 

 specimens dredged by the ' Challenger ' Expedition. The mantle in the dorsal valve 

 of one of the specimens showed in a most distinct manner the four principal pallial 

 simises, which again branched as they approached the front margin of the shell, 

 and bifurcated again before reaching the margin. 



6. Liothyris Bautletti, Dall, sp, (Plate I. figs. 20, 21.) 



Terebratula bartletti, Dall, The American Naturalist, vol. xvi. p. 885, Nov. 1882. 



Shell ovate, globose, longer than wide, broadest anteriorly, dorsal valve convex, with a 

 wide flattened mesial fold of very small elevation, commencing at about two thirds of the 

 length of the valve and extending to the front. Lateral and frontal margins sinuovis, 

 front line of fold nearly straight. Ventral valve slightly deeper and more convex than 

 the dorsal one, with a wide, shallow, flattened, mesial depression or sinus near the front ; 

 beak short, much incurved, overlying the umbo of the opposite valve, and truncated by a 

 small, oval-shaped, incomplete foramen. Surface smooth, marked with concentric lines 

 of growth. Colour light yellowish brown. In the interior of the dorsal valve the loop 

 is short and simple. Length li inch, breadth 1 inch 2 lines, depth 1 inch. 



Hub. Dredged by the United States Coast Survey. Gulf Stream (' Blake ' Expedition) 

 near Vera Cruz, in 218 fathoms. 



Ohs. I have seen one specimen only of this species, kindly lent to me by Mr. Dall. It 

 approaches much in general shape to some specimens of Liothyris vitrea. It differs 

 from Liothyris s]3henoidea {= cuhensis) in the shape of its loop, which is similar to that 

 of L. vitrea. 



7. Liothyris subquadrata, Jeffreys, sp. (Plate II. figs. 15, 16.) 



Terebratula subquadrata, Jeifreys, On the Mollusea procured during the ' Lightning ' and ' Porcu- 

 pine' Expeditious in 1868-70, Proc. Zool. Soc. London, 1878, p. 102, pi. xxii. fig. 3. 



