196 BULLETIN OF THE 



Differs from Z. arboreus, Say, in the smaller spire and wider last whorl; fewer 

 whorls ; differently shaped aperture. It is about half the size of Z. arboreus, and 

 the sculpture is the same as in that species. The Helix Ottonis of Pfeiffer, of 

 which specimens from Cuba and Hayti are before me, has no special relationship 

 to this species, but is undoubtedly a synonym of Z. arboreus, as Pfeiffer himself 

 concluded. H. Ottonis differs from arboreus in nothing but the lighter color; the 

 form and dimensions are precisely as in arboreus. (See Pfr. in Wiegm. Archiv fiir 

 Naturgeschichte, 1840, p. 251 ; the species was never described in the Monographia 

 Heliceorum.) 



The aperture in Z. Dallianus is less lunate than in Z. arboreus, embracing less of 

 the penultimate whorl; seen from beneath, the greater portion of the aperture lies 

 outside of the periphery of the penultimate whorl ; whilst in Z. arboreus the reverse 

 is the case. The much smaller size of Dallianus also separates it from Z. arboreus. 



This species was sent me under the above name by Mr. Charles T. Simpson, the 

 well known student of Floridian shells. The same form I find in the museum of 

 the Academy, collected by Mr. Henry Hemphill. 



The above description was published by Mr. Pilsbry in Proc. Phil. Acad. , 

 N. S., 1889, p. 83, Plate III. Figs. 9, 10, 11. A specimen kindly furnished 

 me for the purpose by Mr. Pilsbry is also figured above. 



Microphysa incrustata, Poet. 

 VOrtex, Pfeiffer. 



All the specimens received from West Florida collected by Mr. Hemphill, 

 and from East Florida by Mr. G. W. Webster, are heavily incrusted with dirt. 



Microphysa (?) dioscoricola, C. B. Adams. 



Shell minute, subperforate, conic globose, thin, very delicately striate, horn- 

 colored ; spire elevated, obtuse ; whorls 3-3-|, convex, the last 

 medially subimpressed; aperture lunately rounded; peristome 

 simple, acute, the columellar margin subvertically descend- 

 ing, very slightly reflected, diam. greater If, lesser If, height 

 H mm. (Pfr.). 



This species is placed by Von Martens (Die Heliceen, p. 73) 

 in Conulus, a subgenus of Byalina, with fulvus, Gundlachi, and 

 Microphysa others. Mr. Dall tells us (Nautilus, III. 25) that it belongs to 



Enlarged 1 *' Microconus. This last is synonymous with Microphysa, a sub- 

 genus of Zonites, according to Tryon, Syst. Conch., III. 24. 

 Mr. Dall says also that the species was originally described from Jamaica by 

 Adams, and subsequently from Trinidad by Guppy as cceca. In its jaw and 

 lingual dentition it seems to agree with most of the other species of Microphysa 

 which I have examined. I retain it, therefore, in that genus. 



The species seems widely distributed in Florida. St. Augustine ; Blue 

 Spring, St. John's River ; Lake Worth to Hawk's Park along the east coast; 

 Hilo River, emptying into Mosquito Inlet, east coast, not Hillsborough River, 

 emptying into Tampa Bay, as stated by Dall. The specimens examined by me 



