124 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



indeed, quite possible that the obscure pamphlet in which Vestinautilus andAsym- 

 pfoceras were introduced might have escaped notice had not de Koninck directed 

 attention to it in his summary of the history of the family Nautilidge (loc. cit.). 

 Their resuscitation by Hyatt has at least the merit of sparing science the infliction 

 of two new names which must have been found for the group of species split off by 

 him from Coelonautilus and SolenocJieilus, to the former of which groups the name 

 Vestinautilus is now applied (type, Nautilus Koninckii, d'Orb.), to the latter the name 

 Asymptoceras (type, N. cyclostomus, Phill.). The types here referred to were both 

 indicated by de Ryckholt himself in the pamphlet quoted above. 



Locality.^— C\&ue, county of Kildare (the only place in which this species has 

 yet been found). 



AsYMPTOCERAs FooHDi, A. Hyatt. Plate XXXII, figs. 1 a, b, 2, 3. 



1891. Soi.ENOCHEiLTJS coNSPicuus, A. H. Foord. Cat. Foss. Cepb. Brit. Mus., 



pt. 2, p. 175, figs. 31 <7, 5 (jjo^ 

 of L. Gr. de Koninck). 

 1893. AsTMrxocEEAS FooEDi, A. Hyatt. Carboniferous Cephalopods. Second 



paper. Geological Survey of Texas, Fourth 

 Annual Eeport, 1892, p. 459. 



Description. — Shell nautilus-like, with about two rapidly increasing whorls, 

 which contract towards the aperture. Section subquadrate. The sides broad, 

 merging imperceptibly into the periphery, which is narrowly rounded in the young 

 and adolescent stages of growth, but from the body-chamber to the aperture 

 it becomes much more broadly rounded, the contraction beginning at about the 

 last fourth of the body-chamber. 



The aperture presents a wavy line, forming a broad and shallow sinus at the sides 

 of the shell, and a deeper hyponomic sinus upon the periphery. In front it is slightly 

 curved forward. Here there is a prominent rim or swelling extending from one 

 umbiHcal margin to the other, and causing the lip of the aperture to be bent 

 inwards. This swelling naturally makes the body-chamber project a little from 

 the rest of the whorl. The umbilicus, the edge of which is obtusely angular, 

 deepens rapidly after the first whorl is completed, the initial whorl leaving a small 

 vacuity in its centre. 



The zone of impression is very shallow and indistinct. 



The incised impression of the shell muscles is more or less distinctly marked 

 upon the cast of the body-chamber in three of the specimens before me. It forms 

 a widely arched, forwardly directed curve from the umbilical margin to the centre 



