214 



Trochus. 



crenularis. . pyramidate, transversely tuberculated, the lower 

 margins of the whirls thickly crenated with large tuber- 

 cles ; columella truncated — 1 inch. 

 Resembling trochus maiiritianus. 



monilifer. . conical, imperforate, transversely granulated in four 

 rows ; columella obliquely subtruncated ; eight concentric 

 rows of grains on the base — f inch. 



sulcatus. . conical, subperforated, transversely and elegantly 

 grooved ; the lower margin prominent. Analagous in some 

 respects wnth T. yranulatus and conulus — | inch. 



alliyatus. . conical, imperforate, spotted ; whirls flat, with six 

 unequal lines, lowest thickest — | inch. 



ornatus. . conical, imperforate ; whirls with numerous oblique 

 ribs on their upper part, on the lower two rows of small 

 tubercles — f inch. 



suhcarinatus. . abbreviated, conical ; whirls smooth, the inferior 

 borders forming an obtuse keel ; base rather convex, finely 

 striated circularly, and perforated — not | inch. 



hicarinatus. . conical, imperforate ; whirls smooth, with two dis- 

 tant keels. 



agglutinans* . . conical, depressed, dilated at the base ; whirls 

 rude, polyedral ; umbilicus internally plaited. 



Solarium. 



patulum. . convex, with smooth whirls, with carinated and cre- 

 nulated borders ; umbilicus open — f inch wide. 



sulcatum . . convex, with radiating grooves beneath ; whirls 

 smooth, with a doubly-grooved border ; umbilicus concave, 

 with crenulated margins — f inch. 



canaliculatum. . convex, with transverse grooves formed between 

 strings of grains ; umbilicus crenated and canaliculated — 

 f inch. 



plicatum. , convex, depressed, rugous, vertically sulcated ; um- 

 bilicus crenated with large plicse — nearly f inch. 



spiratum. . conoidal, smooth, substriated ; whirls flat, subcana- 

 liculated and crenulated in the upper part ; umbilicus gra- 

 nulated and crenulated within. 



ammonites. . depressed, discoidal ; turns flat, with sulcated ver- 

 tical rugae ; umbilicus open, crenated — very small. 



patellatum. . depressed, discoidal, carinated ; turns flat, except 

 on their borders ; a platter-formed umbilicus ; margin sub- 

 crenulated — very small. 



disjunctum. . discoidal, carinated, smooth ; spire flat, lower sur- 

 face convex, the last whirl disjoined ; umbilicus serrated. 



hifrons. . discoidal, obtuse, smooth, spire sunk ; opposite side 

 also subumbilicated, the last turn including the rest — 

 very small. 



* Trochus umbilicaris-- Brand, Foss. fig. 4 ^d 5, nonLinnaei. 



