No abstract

The shell of the freeswimming veliger larval stage of the common North American oyster Crassostrea virginica (Gmelin, 1791) is composed of aragonite. This composition contrasts with that of the adult shell, which is composed mainly of calcite, the rhombohedral allomorph of calcium carbonate, and minor amounts of aragonite.

Pentagonopentagonalis YELTYSHEVA, 1955 (coil. coil.), for species based on crinoid-stem parts [no type species] (ICZN pend.). FAMILY-GROUP NAMES; USE OF "NOM.

Adult oyster shells are composed mainly of calcite, but there are five small areas of aragonite: the resilium, the two pads at which the adductor muscle is inserted, and the two pads at which Quenstedt's muscles are inserted. Quenstedt's muscles are proposed as a name for the small modified, one-time pedal muscles of unknown function, discovered by Quenstedt.

NAME CHANGES IN RELATION TO GROUP CATEGORIES SPECIFIC AND SUBSPECIFIC NAMESDetailed consideration of valid emendation of specific and subspecific names is unnecessary here because it is well underxu