22 AMERICAN JOURNAL 



rank, since this chai^acter differs in every species. In fact it is 

 of only specific value. A. carmata and A. abrujjta are very 

 closely allied, but they should not be separated as a distinct 

 generic group, because, although we do not possess an unbroken 

 series of gradations from them to such shells as A. papillonacea, 

 yet we have many good links in the chain. A. faleiformis, nob., 

 has, in some individuals, a strongly marked angle at the outer 

 anterior margin of the lip, and is not the rounded lobe on. the 

 anterior margin of A. 2^(ipiiio)iacea or of A. Parkinsonii, the 

 rudiment of the same member ? I cannot find any grounds for 

 generic division among such shells as A. abrupta, Con., A. cari- 

 oiata, Mant., A. falciformis, Gabb, A. llequieniara, D'Orb., 

 A. simplex, D'Orb., A. Parkinsonii, Sby., A. Orhiynyana, 

 Pictet, A. Californiea, Gabb, A. Rohinaldina, D'Orb., A. ros- 

 trata, Gabb, and A. paj)ilionacea, Goldf. 



4th. Dr. Stoliczka evidently misunderstands the genus Tessa- 

 rolox. It is a digitate shell, one of the most marked charac- 

 ters being the long, well marked posterior canal running up 

 the spire. It includes but two species with which I am 

 acquainted, both cretaceous — T. distorta, nob., in California, and 

 T. hicarinata, D'Orb., [Pterocera) in France. It possesses a 

 peculiar style of ornament in clavate tubercles on the middle 

 of the body whorl, and differs from Helicaulax, nob., in having 

 the spire more or less encrusted with a thin callus, having also 

 a thin inner lip. In the latter genus the spire is naked and the 

 inner lip is covered by an unusually heavy callus, Avhile the outer 

 lip in all the known species is simply hooked, not digitate. 



5th. Such shells as Aporrhais atraetoides, A. pagodus, Cheno- 

 jnis camelus, C. vespa, &c., can hardly be called congeneric with 

 Aporrhais pespelicani, and should receive another name. 



6th. Diarthema is a good genus, founded on Pterocera para- 

 doxa, Desh., and included by Morris and Lycett in Alaria. It 

 is a comparatively short, sub-fusiform shell, with a short anterior 

 and no posterior canal, no digitations on the outer lip, and two 

 varices like Ilanella. 



7th. I proposed to place Spinigera near the true Mostellarias, 

 but am now inclined to the opinion that its true relations may lie 

 nearer to Alaria and Piarthe7na. It seems not improbable that 

 these shells, bearing varices, may eventually, when we shall know 

 more of the subject, be elevated to the rank of a distinct group. 



Dr. Stoliczka considers Eustomu, Piette, as probably more 

 nearly allied to the Cerithidce than to the " Alata." Its long 

 fusiform shape, the long straight canal, and even the form of the 

 outer lip, seem to me to point to relations with such shells as 



