308 



SOLA RI ELLA. 



This genus was founded by Wood for an English Crag fossil 

 Trochid, conical in form, with tubular whorls and deep umbilicus, 

 its margin crenulated. The type species, S. macnlata, is closely 

 allied to the recent S. amahilis of Jeffreys. The name has been 

 erroneously used by the brothers Adams for a group of tropical, 

 broadly umbilicated, tubular-whorled Trochids, which later received 

 the name Minolia. In 1877, Herman Friele instituted the genus 

 3Iach(Broplax (type M. affinis Jeffr. ,^aviabilis Jeffr. var.), giving as 

 diagnostic charactei's the short broad radula, with few (about 10) 

 uncini, and these much larger and differently formed than in 

 Margarita. The characters of radula may be compared thus: 



Margarita. 



Radula long. 



Median teeth 9-13, subequal, 

 with I'ecurved serrate cusps, 

 and an outer obsolescent cusp- 

 less ])late lying between the 

 perfect median teetii and the 

 uncini. 



Uncini very numerous, the a])ices 

 recurved, denticulate. 



Machceopla.v (^=Solariella). 



Radula short, broad. 



Median teeth 5-7, subequal, with 

 serrate cusps, the obsolescent 

 outer lateral of Margarita re- 

 placed by a well-developed 

 tooth with denticulate cusp. 



Uncini few (about 10), large, 

 falciform, with entire or feebly 

 denticulate ed^es. 



The little group separated by the writer under the name Conotro- 

 chns may, as Dr. Dall has suggested to me, belong to Solariella; but 

 as its relations seem to be equally close to Minolia, I include it for the 

 present in that genus as a section. (See page 197, 2H8.) 



The dentition and operculum of 8. varicosa ai-e figured on pi. 50, 

 figs. 7, 17. 



S. OBSCUEA Couthony. PI. 57, figs. 44, 45. 



Shell umbilicate, conical, thin, ashen, whitish or reddish in color ; 

 surface lusterless, the dull outer layer very thin, overlying a brill- 

 iantly iridescent nacre. Sculpture consisting of a rather prominent 

 spiral ridge or carina at the shoulder of each whorl, beneath which, 

 on the peripheral portion of the whorl, there are several (generally 

 3 to 6) smaller lirje, often subobsolete ; the entire base sometimes 

 shows fine low concentric lira", but usually they nearly disappear 

 there, becoming visible again around the umbilicus; there are often 

 traces of a few obscure spiral riblets above the supra-peripheral 

 carina. Longitudinally the entire surface is marked by regular. 



