162 J. 8. Gardner — On the Gaidt Rostellarim. 



1. — Bostellaria, Lamarck. 



Shell pointed, prolonged, turriculated, the mouth terminated ante- 

 riorly by a thin rostrated canal ; the lip forms a but little developed 

 wing, which has on its margin small pointed teeth. The posterior 

 angle of the mouth generally presents a canal contiguous to the 

 spire. In all recent species there is a want of ornamentation ; the 

 surface is smooth or reticulated, but does not present prominent 

 costee, analogous to those which are so frequent on Chenopus and 

 Fteroceras. 



2. — Aporrhais, Da Costa. (Chenopus, Philippi.) 



In the small number of species which are known the shell is 

 turriculated spire, long or median, with a considerably expanded 

 wing, more or less divided, and a variable anterior canal. 



A comparison of the shells, which may easily be made at the 

 British Museum, confirms the foregoing descriptions. It will be 

 observed that all the species of the genus Aporrhais are strongly 

 ornamented, and the difference in aspect will strike the most casual 

 observer. Their separation has, I believe, been made on account of 

 differences in structure of the animals themselves. 



A careful and unbiassed examination will, I feel convinced, lead to 

 the conclusion that all the Gault Bostellarice should be named 

 Aporrhais, for they undoubtedly bear considerably more resemblance 

 to Aporrhais pes-pelicani and A. occidentalis, than they do to any of 

 the Bostellarice. Indeed, they are even more like Fteroceras than 

 Bostellaria, and can often only be distinguished from the former by 

 the length of their spire. 



I have ventured to subjoin a list of the species from the Gault in 

 my collection. I shall be happy to place them at the disposal of and to 

 assist any practical paleontologist who desires to give a really ex- 

 haustive account of this most interesting group, which seems to have 

 reached its maximum development at this period of the Cretaceous 

 epoch. The species are best preserved and most abundant at Folke- 

 stone. It must be understood that the following is a hurried list, 

 and merely provisional. The subject wants most careful treatment 

 and illustration from perfect specimens existing in different cabinets. 

 If it serves to provoke discussion and call attention to the group, my 

 object will have been attained. 



1. Aporrhais (Pict.) carinata. Sow. 



2. Aporrhais Orbigmjana, Pict. et Roux (qy. A. obtusa, Pict.) R. costata of 



Michelin, but described under a false assimilation with, a different species found 

 at Gosau. Very abundant. 



3. Aporrhais Parkimoni, Sow. Much confusion has arisen from different species 



having been figured by Mantell, Sowerby, and D'Orbigny under the same 

 name. According to strict precedent, the species figured by Parkinson, and 

 known to English geologists as R. Rarkinsoni, has the priority, and should be 

 retained instead of R. Reussii, R. buccinoides, etc. 



4. Aporrhais calcarala, D'Orb. (and qy. A Muleti, d'Orb.). A small species, also 



common at Blackdown. 



5. Aporrhais carinella, D'Orb. A smooth species, figured by D' Orbigny in Pal. Fr., 



but imperfect in his figure. 



6. Aporrhais, a distinct elongated species, the elongata of Sowerby, Geol. Trans., 



2nd ser., vol. iv., pi. xi., fig. 17, appears to be a Scalaria. I should propose 

 to retain the specific name elongata for thia species. 



