NEW MOLLUSCAN GENP]RA FROM THE CARBONIFEROUS." 



By Geouce H. Girty, 



Cuslodlaii of CdrhoiiiJ'croiis Innniehrutr Foi<hUs. 



Among- the Carboniferous faunas examined in the course of investi- 

 gations connected with othcial work, 1 have been hnl to recognize a 

 large numl)er of undescribed species and some genera, which in most 

 cases it did not seem appropi'iate to make known in connection with 

 the studies that brouglit them into notice. IShuiy of tliesc types 

 were laid aside for discussion with one or another of a number of 

 subjects the investigation of which is projected. Thei'e remains, how- 

 ever, a collection very miscellaneous in character and not germane to 

 any of the papers now in view. A few of the generic types it is here 

 proposed to describe and name. 



In order to secure brevity in the title of this paper, the term raol- 

 luscan is employed in a somewhat broader sense than present jusage 

 generally saiK'tions, though not inconsistently with that of the last gen- 

 eration by which brachiopoda were grouped with the true mollusca. 



The fossils upon which the observations recorded in this paper were 

 made form part of the collections of the U. S. National Museum. 



LIMIPECTEN,'' new genus. 



It is rare that one is able directly to ol)serve structural characters 

 in Carboniferous Pectinoids. Usually either the shell is embedded in 

 hard rock, from which it is hopeless to clear It, or else, and this is the 

 best that happens, the test has been dissolved away and the structures 

 are seen in reverse as casts. A few examples from Young County, 

 Texas, however, which have recently come under ni}^ observation, 

 though more or less fragmentary, retain their original .shell substance 

 completely and show characters which indicate that they are distinct 

 from anv of the genera thus far defined. I will tirst describe this 



_ 



form, which .seems to belong to a new .species as well as to an unknown 

 genus, in detail, and then consider the characters by which it is 

 distinct from related genera. 

 Genotype. — Limipecten texanus. 



a Published by permission of the Director of the V. S. Geolofrioal Survey. 

 &From Luna and Pecten, two Telecypod genera. 



Proceedings U. S. National Museum, Vol. XXVII— No. 1372. 



721 



