802 PROCEEDINGS OF Till: XATIOX.iL 



tQUADRULA CORNUUM LUN^E Heude.' 



* U.iio montanus HEUDE, Conch. Fluv. Nank., I, 1875, pi. iv, fig. 11. *P.KTKL, 



Conch. Sam., III, 1890, p. 159. 

 I'nio cornuitm-lunai HEUDE, Couch. Fluv. Xank.. VIII, 1883, pi. i.vn, fig. 105. 



* P.ETEE, Couch. Sam., Ill, 1890, p. 149. 



* Unio trisulcatus HEUDE, Couch. Fluv. Xauk., VIII, 1883, pi. LVH, fig. 108. 

 *Unio paschaUs HEUDE, Couch. Fluv. Xank., VIII, 1883, pi. j.vm, fig. 110. 



* P^ETEL, Conch. Sam., Ill, 1890, p. 162. 



' f'nio rerrucu1o8U8 HEUDE, Couch. Fluv. Nank., VIII, 1883, pi. i.vm, fig. 111. 



* P^TEL, Conch. Sam., Ill, 1890, p. 171. 



* Unio aborting HEUDE, Conch. Fluv. Nauk., VIII, 1883, pi. i.xin, fig. 124. 

 *Unw vionticola HEUDE, Jl. de Couch., XXXII, 1884, p. 19. 



QUADRULA CORNUUM LUM^E var. CINNAMOMEUS Gredler. 



*Unio leai var. clnnamomens GKEDLEK, Jahrh. Deuts. Mai. Ges., VIII, 1881, p. 122, 

 pi. vi, fig. 16. 2 * PJETEL, Conch. Sam., Ill, 1890, p. 157. 



China. 



QUADRULA SCRIPTA Heude. 



* Unio scriptus HEUDE, Conch. Fluv. Nauk.. 1. 1875, pi. in, figs. 8, 8. "P.KTKL. 



Conch. Sam., Ill, 1890, p. 167. 



China. 



QUADRULA DIVERGENS Benson. 



Unio divergens BENSON, .11. As. Soc. Beug., XXIX, 1855, p. 137. 3 

 Chusan Island, China. 



Subgenus DISCOMYA Simpson, 1900. 



Shell subsolid, round obovate or subrhomboid, lenticular, rather com- 

 pressed, widely, faintly biangulate behind, with scarcely any vestige of a 

 posterior ridge; beaks very low, sculpture not seen; front half of the 

 shell densely covered with fine pustules arranged in curved rows in two 

 directions as if engine chased, over which the epidermis is wrinkled. 

 The hinder half is covered with flue, radiating and undulating corru- 

 gations, curved upward posteriorly, which are slightly nodulous and 

 show through on the inside of the shell ; one slightly compressed pseudo- 

 cardinal in the right valve and two in the left; one delicate, curved 



1 First called montanus by Heude, which Avas several times preoccupied iu Unio. 



3 Gredler makes this a variety of leai, hut I believe it is a rather finely sculptured 

 form of moniicola. The species varies much in the size of pustules and the degree of 

 its smoothness, and Heude has exalted all these variations to the rank of species. I 

 think it probable that when a large amount of material can be examined it will be 

 found necessary to reduce some of the Chinese forms I have considered as species to 

 the rank of varieties, or even to the synonymy. 



3 Benson says this is not very distantly related to J'nio nudulatus Barnes. It has 

 never been figured, so far as I know, but from all I can learn of it it belongs in this 

 group and may be Q. leai. 



