OF CONCHOLOGY.. 65 



Page 123. Terebratella rubella, Sby., is a Laqueus, and is 

 the same as L. suffusus, n. s. ? Dall, p. 125. Sowerby's name 

 has priority. Mr. Davidson has compared specimens of Laqueus 

 suffusus with the types of rubella, and finds them identical, 

 though the coloration varies very greatly. In this decision I 

 cheerfully acquiesce. 



Terebratella suffusa, Reeve, p. 122. 



Mr. Davidson, who possesses the typical specimen of this 

 species, having examined the apophyses, kindly informs me that 

 it possesses the " large elevated septum and loop of Magasella, 

 to which subgenus it will require to be referred." The species 

 described by me at p. 122, and figured (pi. vi, fig. 4) in my first 

 paper, being- a true Terebratella, and not, as 1 supposed, the 

 species described by Reeve, may take the name of Terebratella 

 rubiginosa. 



Add Terebratella spitzbergensis, which is erroneously referred 

 to the subgenus Magasella at p. 127. 



Subgenus Ismenia, p. 127. 



Zittel, in Dunker and Von Meyer's Paleontographica, Aug., 

 1870, has figured the interior of many species of fossil Brachi- 

 opods. Among them is Terebratula pectunculus, Schloth., which 

 proves to have the lateral loops closed, so that it is nothing more 

 than a Megerlia. The diagnosis of Ismenia on p. 127 refers to the 

 recent species only. These shells, by their smooth surface, oblong 

 shape, thin shells, and open lateral loops, differ greatly in appear- 

 ance from the sculptured, transverse, thick Megerliai with closed 

 loops ; and, since the /. sanguinea was the first species in Dr. 

 Gray's Catalogue, it may be well to retain the name of Ismenia 

 for the recent species alluded to above in a subsectional sense. 



Ismenia ? Jeffreysi, Dall. PL 11, fig. 7-10. 



Under the name of Frenula Jeffreysi I published in the 

 American Naturalist (V, p. 55, March, 1871,) a provisional de- 

 scription of a few lines referring to a shell which may be de- 

 scribed as follows : 



Shell magaselloid in external appearance, smooth, with an in- 

 complete horseshoe-shaped foramen. Without a septum in either 

 valve. Loop unattached, except by the haemal processes to the 

 hinge plate. Loop complex, somewhat like that of Ismenia san- 

 guinea. Crura well marked, long and slender in the adult. 

 Haemal processes connected, the connecting band produced into 

 a sharp point in the median line with a sinus above it ; the point 

 produced toward the haemal valve, below the haemal processes. 



