102 



THK NAUTILUS. 



advertence. Amoeroecium is a genus of compound Ascidians. Ver- 

 rill, in his Rep. on Invert, of Vin. Sound, 1873. notices (on dififerent 

 pages) both Amoeroecium pallidum and Onchidoris pallida which 

 latter is of course what Mr. Lermond intended to cite. 



Pallida is, however, a synonym of Lamellidoris aspera (A. & H.). 

 The entry, therefore, should stand as Lamellidoris aspera (A. & H.) 

 with Proctaporia fusca Stimps. 1860, Doris pallida Ag. 1849, and 

 Onchidoris pallida " Verrill," Verrill 1870 and 1873, in synonymy. 



Lamellidoris muricatus should be written muricata. 



Palio lessoni should be written lessonii. 



TJRIONID^ FKOM SOUTHEASTEKN AEKANSAS AND N. E. LOUISIANA. 



BY E. G. VANATTA. 



Mr. Clarence B. Moore collected the following species of Unionida 

 while on an archaeological expedition during the winter of 1908-09. 



Quadrula ebena Lea was everywhere the most abundant species. 

 Dr. Pilsbry agrees with me in considering Uiiio domheyana Val. in 

 Humboldt et Bonpland, Rec. Obs. Zool,, 1833, Vol. 2. p. 227, pi. 

 53, f. 1, a valid variety of Quadrula heros Say, instead of a synonym 

 of Q. trapezoides Lea. 



The originally varietal name ohesa Simps, is used instead of 

 Tritogonia tuberculata Bar. as the name tuherculata is preoccupied in 

 Quadrula. Unio tuherculatus Barnes was grouped with U. apiculatus 

 (now referred to the genus Quadrula) by Pilsbry in 1891 (Nau- 

 tilus V, p. 76) ; a position confirmed by Dr. H. von Ihering in 

 1901 (Nautilus XV, p. 39), and by Dr. Arnold Ortmann this 

 year. (Ann. Carnegie Mus., 1909, Vol. 5, p. 193.) 



All the specimens of Quadrula trapezoides, pyramidata, ehena, 

 obesa and Plagiola securis were smaller than the usual size. 



I. Pyles Landing, Ouachita River, Calhoun Co., Arkansas. 

 Obovaria castanea Lea and Anodo7ita opaca Lea. 



IL Near Pigeon Hill, Ouachita River, Union Co., Arkansas. 

 Obovaria castanea Lea. Quadrula plicata Say. 



Plagiola securis Lea. " heros dumbeyana Val. 



" elegans Lea. " metanevra Raf. 



Strophitus edenlulus Lea. " asperrima Lea. 



Unio subgibbosus Lea. " obesa Simps. 



