BRACHIOPODA-MOLLUSCA 



21 



Phylum BRACfflOPODA 



Class INARTICULATA 



Class ARTICULATA^ 



Order ATREMATA 



Lingula; Glottidia 

 Order NEOTREMATA 



Crania; Discinisca 



Sub-order Thecideoidea 



Lacazella 

 Sub-order Rhynchonelloidea 



Hemithyris; Cryptopora 

 Sub-order Terebratuloidea 



Gryphits; Terebratulina 

 Sub-order Terebratelloidea 



Argyrotheca; Dallina; Terebratella; Magellania 



Phylum MOLLUSCA 



Class POLYPLACOPHORA* 



( = Loricata) 



Class APLACOPHORA* 



( = SOLENOGASTRES) 



Class MONOPLACOPHORA 



Class GASTROPODA 



Order LEPmOPLEURIDA 



Lepidopleurus 

 Order CHITONIDA 



Chiton (coat of mail shell); Cryptochiton; 

 Lepidochiton ( =Lepidochitona) 



Order NEOMENIOMORPHA 



Ne omenta; Proneomenia 

 Order CHAETODERMOMORPHA 



Chaetoderma 



Order TRYBLIDIACEA 



Neopilina 



Sub-class PROSOBRANCHIA 



( = Streptoneura) 



Order ARCHAEOGASTROPODA 



( = Diotocardia, Aspidobranchia) 

 Acmaea (limpet); Megathura (keyhole limpet); 

 Haliotis (ear-shell, ormer, abalone) ; Patella 

 (limpet); Nerita; Pleurotomaria; Trochus (top-shell) 



' The Articulata (see also Crinoidea, p. 32) used to be divided into two orders, Protremata and Telo- 

 tremata. Tliese overlap and have therefore been discarded. They have not so far been replaced, though the 

 ordinal classification of the Articulata is under review. 



' These two classes are sometimes grouped together as Amphineura. 



