Bay of Bengal and the Arabian Sea. 11 
A. philippinarum is more pointed behind, not so triangular, 
the umbones being less prominent, and the dorsal margins are 
less oblique than in the present species. The hinge, liga- 
ment-pit, muscular sears, and the inner surface of the Trallves 
are similar in both. In all three forms the umbo in the 
left valve is the slightest, more prominent than that of the 
right. 
Poromya (Cetoconcha) tornata, Jeffreys. 
ee tornata, Jeffreys, Ann. & Mag. Nat. Hist. 1876, vol. xviii. 
. 494, 
ey tornata, Smith, Lamellibranchiata ‘Challenger’ Exped. 
p. 170, pl. xxv. tigs. 9-95; Pelseneer, Anatomy Deep-sea Mollusca 
‘Challenger’ Exped. p- 20, 
Hab. Station 110, lat. 9° 34’ N., long. 85° 43’ 15’ E., 
east of Ceylon, in 1997 ie 
Beyond a very slight difference in form there is nothing to 
separate the single specimen from the above locality from 
this species, hitherto" only known from great depths 
(1850 fathoms) in the Atlantic. It differs from the two 
specimens obtained by the ‘ Challenger’ in being very slightly 
longer, or, in other words, the ends have a faintly produced 
appearance. But the two Atlantic sheils are not exactly 
similar in form, a character which is liable to variation in 
every species. The sculpture and _ hinge-characters are 
exactly the same in all. To show how slight is the difference 
in the relative proportions of the Atlantic and Indian-Ocean 
specimens, I append the following measurements :— 
Length. Height. Diam. 
willim. millim. wmiJlim. 
Atlantie’specimén =... 2). °lS4 133 10 
Indian-Ocean specimen . . 143 134 104 
Pelseneer has shown that this species is anatomically the 
same as Poromya, not Verticordia. 
Solenomya patagonica, Smith. 
Solemya patagonica, Smith, Lamellibranch. ‘Challenger’ Exped. 
p- 208, pl. x1. figs. 1, la. 
Hab. Off west coast of Patagonia, in 245 fathoms (‘Chal- 
lenger’); Station 151, off Colombo, in 142-400 fathoms 
(‘Investigator’). 
‘Lhe single Indian-Ocean specimen is a little smaller than 
the type, and was dredged alive. ‘lhe valves do not exhibit 
the thickening within, beneath the hinge-line, referred to in 
