66 AMERICAN JOURNAL 



Lateral loops open. Anterior extremities of the haemal pro- 

 cesses produced into sharp points. Reflected portion of the loop 

 broad, connected by perpendicular lamellae to the haemal band 

 between the haemal processes, and by lateral extensions to the 

 haemal processes themselves. 



Shell smooth, waxen, with close conspicuous punctations ; sub- 

 circular, compressed, with the margin of the valves nearly 

 straight. Area marked by an incised line, deltidia wanting; the 

 two separated parts of the area narrow, and very small. Beak 

 of the haemal valve rather prominent, smooth. Neural beak in- 

 curved, truncated, not prominent. Lon. '34, Lat. "33, Diameter 

 •17 inches. Hah. N. E. Atlantic; 155 — 345 fathoms with W. 

 cranium, Jeffreys. Norway; with same, MacAndrew. 



The specimen from which the above description was drawn up 

 had the apophyses, which are accurately represented in the ac- 

 companying figures, in a beautifully perfect state of preserva- 

 tion. My largest specimen had the loop partially broken away 

 but unmistakably belonged to the same species. None of the 

 specimens had the slightest trace of a septum, and the shell ap- 

 pearing quite different from anything which has been figured 

 in the works accessible to me, I felt justified, perhaps too hastily, 

 in considering it as a new form. Since that time, by the kind- 

 ness of Mr. J. Gwyn Jeffreys, I have had the opportunity of ex- 

 amining a number of young shells which had been referred to 

 Terebratella Spitzbergemis and Waldheimia cranium as being 

 the young state of one or the other of those species. One of 

 these shells contained the apophyses in a perfect condition, but 

 evidently abnormally distorted and malformed, being unsymme- 

 trical and having the loops much compressed and abnormally 

 united together. All of them possessed a filiform but rather 

 stout septum. The appearance of these shells was so like that 

 of the species above referred to, that, while I am not certain 

 that they are identical, I feel pretty confident that they are the 

 same, and that in the specimen figured and the others, which 

 were broken, the septum must have been broken away, and left no 

 trace of its existence. As it is slender and cylindrical it is pos- 

 sible that this may have happened. At all events, I am unwill- 

 ing, without further material, to describe the shell more than 

 specifically. The open loops, if the above surmises prove cor- 

 rect, would place it in the section Ismenia of the genus Megerlia. 



Megerlia truncata, Lin., p. 130. T. monstruosa, Sacchi, must 

 be removed from the synonymy of this species. It is a Megerlia y 

 but a probably distinct species, according to Mr. Davidson. 

 Platidia Davidsoni, Desk, may be a synonym of it, but the in- 

 terior of this last is unknown, and judgment must be suspended 



