SYNOPSIS OF THE ANIMAL KINGDOM 385 



NEMATHELMINTHES. Bilateral, unsegmented, round-worms; 

 usually with alimentary tract, mouth, and anus: Ascaris (151). 



ROTIFER A. Small aquatic Scolecida, with ciliated band around 

 mouth, and a special organ for attachment, the foot; wheel-animal- 

 cules. 



BRYOZOA. Scolecida in which the ciliated band is carried out 011 

 a series of tentacles surrounding the mouth ; form colonies by bud- 

 ding. ENDOPROCTA, Bryozoa with head and stalk, and crown of tenta- 

 cles surrounding both mouth and anus (1-43). ECTOPROCTA, with 

 anus outside tentacular corona (143). 



MOLLUSCA i 



Animals with unsegmented body and without jointed appendages. 

 Usually with a shell and with a muscular organ of locomotion, the 

 foot. 



LAMELLIBRANCHIATA. Mollusca with nearly symmetrical 

 body, leaf-like gills, and a shell composed of two valves. Ledidce 

 (187); Arcidce (184); Mytilidce (184); Aviculidce (185); Pectinidce 

 (186) ; Ostreidce (187) ; Unionidce (179) ; Cycladidce (180) ; Mactridce 

 (182); Veneridce (183); Myidce (182); Solenidce (182); Pholadidce 

 (181); Teredidce (181). 



GASTROPODA. Mollusca with head, feelers, and eyes, an un- 

 paired foot, and a shell that is univalve when present. AMPHINEURA, 

 with strict bilateral symmetry, no externally visible gills, and usu- 

 ally a shell composed of eight pieces: Chiton (171). PROSOBRANCHI- 

 ATA, with gills in front, shelled and operculate : Acmceidce (170) ; 

 Patellidce (170); Fissurellidce (170); Natiddce (168); Calyptraidce 

 (Crepidula, 169) ; Littorinidce (167) ; Muricidce (Urosalpinx, 169) ; 

 Fasciolariidce (Fulgur, 168) . OPISTHOBRANCHIATA, with gills behind 

 heart; if shelled, without operculum ; JEolidiidce (171). PULMONATA, 

 breathing by means of lungs, no operculum : Auriculidce (165) ; Lim- 

 nceidce (166) ; Limacidce (161) ; Helicidce (164) ; Pupidce (165). 



CEPHALOPODA. Mollusca with large head, mouth surrounded 

 by a circle of arms, and funnel-shaped foot. Argonautidce (172); 

 Spirulidce (172) ; Loliginidce (172) ; Nautilidce (173). 



1 This classification, unlike that of the text, follows Cooke in his " Mol- 

 lusca." 



2c 



