256 ME. J. W. GEEGOEY ON THE 



Affinities. This appears to be a very well-marked species, with its elevated 

 peristome, its tumid front wall, and its large lateral avicularia and marginal punctures. 

 The secondary orifice is so raised and subtubular that it first seemed that the species 

 belonged to Porella (or Tessarodoma) ; but its secondary orifice and external avicularia 

 show that the resemblance is superficial and that it is truly a Smittia. Its mode of 

 growth, however, is exactly that of Tuhucellaria ; it lacks, however, the peristomial pore 

 of that genus, and the peristome is not so raised. It is not improbable that some of 

 the specimens figured as fossil forms of T. opuntioides (Pall.) may belong to this 

 species. Such may be the sjjecimen figured by Michelin [No. i, pi. 46. fig. 21] as 

 Vincularia fragilis, Defr., and some of Reuss's Cellaria michelini. 



Smittia is well known in the Continental Upper Eocene and Oligocene i, but none 

 of the species with which I am acquainted sufficiently resemble this one to necessitate 

 a comparison. 



Order CYCLOSTOMATA. 



Family IDMONEIDiE. 



Genus Idmonea, Lamouroux, 1821. 

 [Lamouroux, No. 2, p. 80.] 



Diagnosis. Pergens, No. 3, p. 342. 



Type species. Idmonea triquetra, Lamx. No. 2, p. 80, pi. 79. figs. 13-15. 



Species 1. Idmonea giebeli, Stoliczka, 1862. 

 Syn. Idmonea (Tubiffera) giebeli, F. Stoliczka, 1863, Olig. Bry. Latdf., Sitzb. k. Ak. Wiss. Wien, 

 Bd. xlv. p. 81, pi. i. fig. 6 ; F. Schreiber, 1872, Bry. Mittelolig. Griinsand Magdeburg, 

 Zeit. f. gesammt. Naturwiss. Bd. xxxix. p. 479. 

 Idmonea giebeliana, F. Stoliczka, 1865, Foss. Bry. Orakei Bay, Novara Reise, Geol. Theil, Bd. 

 i. Abth. ii. PaL p. 115, pi. xviii. figs. 4-6 j F. W. Hutton, 1880, Man. New Zeal. Moll. 

 Coll. Mus. Geol. Surv. N.Z. p. 196. 

 Diagnosis. Zoarium cylindrical, straight, erect branches; mode of branching unknown. 

 The back of the zoarium is a full flat curve ; the front is well raised. 



Zooecia in series of five ; one forms a median row, on each side of which are two pairs 

 placed on a line a little above the central zooecium. The outermost zooecia are the 

 longest, but only slightly exceed the others. The walls are granular. Peristome 

 entire, even. 



Ooecia small, replacing one of the median zooecia. 



' See e.g. Waters, No. 12, pp. 21, 22. 



