390 



ECHINOLAMPID^. 



This definition unfortunately embraces forms which appertain to several genera. 

 Even the three species figured as Echinanthus, in Tab. iv, of Breynius's work, from the 

 position of the vent, represent two distinct types. 



The EcHiNOLAMPiDiB resemble the EcHiNOBRissiDiE in the general organization of 

 their test ; but the species are distinguished from those of that group by the position of 

 the vent, the development of the peristomal lobes, the basal ambulacral rosette, and by the 

 tubercles, in some genera at least, being perforated. 



In the following table I have given a short diagnosis of the genera, and include in the 

 family Echinolampid^, together with their stratigraphical distribution in time. 



A Table showing the Classification and Distribution or the EchinolampidjE, 



Family. 



Pi 



o 



o 



Diagnosis. 



Test, oblong, inflated ; petals long, narrow, 1 

 nearly reaching the border ; vent trans- r 

 verse, supra-marginal. J 



Test oblong, depressed ; petals short, nar- "| 

 row, limited to the dorsum; vent oval, r 

 marginal, or supra-marginal. -^ 



Test ovoid or discoid ; petals wide, long, T 

 nearly reaching the border ; vent, trans- > 

 verse, infra-marginal. J 



Test large, discoidal, or elevated ; petals "1 

 large, long, reaching the border ; vent I 

 infra-marginal, longitudinal, surrounded | 

 by a distinct area. ' 



Test oblong, depressed ; petals long, nar- ■» 

 row, reaching the border ; vent longitu- I 

 dinal, marginal. J 



Test elevated, or conical ; petals narrow, 

 lanceolate, short, limited to the dorsum 

 vent small, transverse, without area ; base 

 flat, without elevation. 



Test large, oval or circular, much elevated, 

 or conoidal ; petals long, straight, wide, 

 equal, not contracted below ; vent infra, 

 marginal, triangular ; base flat. 



;i 



Genera. 



Formation. 



Pygorhynchus, Agassis. 



Tertiary. 



EcHiNANTHUS, Breynius. 



Tertiary and Upper Creta 





ceous. 



EcHiNOLAMPAS, Grey. 



Living and Tertiary. 



Pygurus, Agassiz. 



Cretaceous and Oolitic. 



BoTRiOPYGUS, D'Orbigny. 



Cretaceous. 



Faujasia, jyOrbigny. 



Upper Cretaceous. 



CoNOCLYPUs, Agassis. Tertiary and Cretaceous. 



