1883.] 299 [Hyatt. 



and sutures can be more or less closely compared with the young 

 of Barrandeoceras, the adults of Nephriticeras, and the adolescent 

 of the large Carboniferous forms, like Naut. eximius, and prsegra- 

 vis, DeKon., Calc. Carb. Type, Uran. (Cyrt.) Uranum, sp. Barr. 

 pi. 196. 1 I have met with several specimens of this, or a closely 

 allied species, from Anticosti, Mus. McGill. Coll., Bost. Soc. Nat. 

 Hist., and Mus. Can. Geol. Surv. The exact radicals of this genus 

 are unknown, but it has close relations with Spyroceras in its 

 sutures ; and the form of the whorl in U. Uranum is very similar 

 to the laterally compressed and flat abdomened forms of Spyro- 

 ceras. 



Barrandeoceras, 2 nobis, includes gyroceran andnautilian shells 

 with very large umbilical perforations, and compressed, slightly 

 costated or smooth whorls, generally without an impressed zone, 

 though this is sometimes present. The venter is narrower than 

 the dorsum, the siphon near but above the centre, septa deeply 

 concave, and sutures with ventral saddles, lateral lobes and dor- 

 sal saddles, without annular lobes. Type, Barr. (Naut.) natator, 

 sp. Bill. Can. Nat. n. s. Yol. 4, Mus. Geol. Surv. Can., The genus 

 also includes the Bohemian forms Barr. (Naut.) Bohemicum, sp. 

 Barr. Yol. 2, Syst. Sil. pi. 32, 33, Sternbergi, ibid, pi. 36, 37, ty- 

 rannus, ibid., pi. 38, Sacheri, ibid, pi. 39. Living chamber is 

 about one-half of a volution in length ; it is about three-fourths 

 of a volution in length in the type species. 



Pselioceras, 3 nobis, includes the series of Dyassic Ophionei, 

 traced by Waagen in his fossils of the Salt Range, Pal. Ind, Ser. 

 13, pt. 1, Pisces and Cephalopoda. The large umbilical perfora- 

 tion of the type, Psel. (Naut.) ophioneum, sp. Waagen, ibid, pi. 5, 

 fig. 2, shows that it must have been cyrtoceran in the earlier 

 stages for a prolonged period. There is a slight dorsal impressed 

 zone formed, according to Waagen's figures, after the close coiled 

 stage begins, on the first whorl. The resemblance of this genus 

 to the adults of Barrandeoceras natator is very close in the sut- 

 ures, and form of the larval and adolescent stages. We place it 



provisionally in the same series, noting, however, that the forms 



1 Barrande has also noted the Nautilius-like aspect of this species. 



2 This genus was dedicated to M. Joachim Barrande, before his death, as a token of 

 respect and admiration for his work upon the fossil Cephalopods. 



8 ^ Aaov, a bracelet. 



