[01 ll\... ill i , 



1 ferpeoter, 1*7*. 



, i/\. mid tahl.- of i;- ci.it : 



Proc. r. s. N : ,t. M.IS. I.STS, P . 830, type G maj B 



M<tu<i<-,;ii c\'\i. .J/x. and table of Reg. Chi'toof, type .i/ 



Cpr. .l/.S'. Iwhnortnltin (in pan . SIM i i i.i.u .. I ' m. Mill heil. ! 

 p. 86, 



Like Stenoplax, hut intermediate ralvee 1 1 aving several rid 

 The Uadsioid valves alone di.-iin_iruisli tliis from Stenoplax. Its 

 relations \\itli the Australian Stenochiton. jntuid<' an; jirolmlily not 

 especially close. 



In one species, /. conspicuus, the mantle scales have Ixrn ti 

 formed into slicrt, round, striated bristles, and on account oftlii- 

 modification Carpenter established for it a subgenus under Chceto- 

 jt /en rn which he called Maugcrella. We are com pel led to.-nppr-.- thi* 

 group because of the excessively close relationship <-xi.-tinir lM-t\\--n 

 /. conspicHitx and the two species of genuine Sten- 

 and /. magdalenensis. 



I. ACRIOR Carpenter, n. sp. PL 14, figs. 86-89. 



Shell much like /. magdalenensis, but broader and flatter, with 

 much sharper sculpture. Olive-green, pink where worn, or > 

 times light flesh-colored, with the jugum or central areas often 

 green. Girdle dark ashen or olive. 



The anterior valve is notably concave, as in /. conspicuus. Tin- 

 lateral areas are much raised, and sculptured with acute radiating 

 riblets, sometimes splitting; central areas having acute longitudinal 

 riblets. 



Interior pink, with a blue spot at the jugal sinus. Sutural p! 

 wide, pink; sinus broad, deep, angular. Anterior valves having 

 13-15, central valves 2-4, posterior valves 10-13 slits. Teeth long, 

 sharp, smooth. Eaves wide, dark-blue. 



Girdle wide, tough, covered with very small, solid, shot 



Length 110, breadth 55 mill. 



Length 75, breadth 40 mill. 



Cerros (Cedros) Island to Cape St. Limn.*, Lower California, 



StenoradsiaacriorCpR.MS. Chiton iintfjd'i/eneimiin part Ki i 

 Conch. Icon. t. 4, f. 20a, not of Hinds. 



This species represents one extreme of variation of the / 

 magdalenensis type, the other extreme being 7. con^icun.<. 1 i 



