GLOSSARY OF DESCRIPTIVE TERMS AND GENERAL INDEX 

 (Sections, Genera, etc., in Separate Index) 



Abyssal region.... p. 5 



Acoela p. 144 



Acuminate. .. .Sharp pointed 

 Acute. .. .Sharp edged or pointed 



Admedlan teeth Portion of radula, p. 18 



Adnate. .. .Growing together, connected 



Alated. . . .With wing-like projections. Fig. SO, 



p. 16 

 Amphlneura. . . .A class, pp. 1, 22 

 Analogous. .. .Parallel, similar, related 

 Anatomy. .. .The study of the structure of organ- 

 isms as shown by dissection 

 Anterior end.... In bivalve shells the opposite 

 end to which the ligament is attached; the 

 front of the shell in life 

 Aperture. .. .The opening, p. 14 

 Apex. .. .Summit or place of beginning of uni- 

 valve shells 

 Archaeogastropoda. . . .p. 74 

 Archlbenthal region.... p. 5 

 Articulated. .. .See operculum, p. 14 

 Attached. .. .Fixed to some solid object 

 Auriculate. .. .Eared or with processes like those 



in Pecten 

 Auriform. .. .Shaped like the human ear 

 Axis.... An imaginary center around which the 

 whorls coll 



Basal margin. .. .Margin opposite the umbones, 



corresponding with foot of animal in bivalves 



Base (in univalves) ... .Extremity opposite to the 

 apex 



Beak. .. .Sharp pointed anterior end of a bivalve 

 shellj formerly used to describe the extremi- 

 ty of the umbo 



Biangulate. .. .Doubly keeled as in Tectarlus nod- 

 ulosus, PI. 37, Fig. &i 



Bifid. .. .Divided at the tip into two parts 



Bivalve. .. .Composed of two pieces, rarely en- 

 closed in a tube as in Teredo 



Byssus. .. .Beard-like filaments proceeding from 

 the animal and used for attachment to some 

 solid object, p. 17 



Cabinet p. 7 



Calcareous. .. .Of shell substance 



Callus.... A calcareous deposit such as enamel 



Camera.... p. 10 



Canal. .. .Descending groove in aperture of an un- 

 ivalve 



Cancellated. .. .When horizontal and vertical 

 lines, of similar strength, cross; cross- 

 barred 



Carinate. . . .When whorls are strongly keeled as 

 in Astraea 



Cephalopoda. .. .A class, pp. 1, 148 



Ciliate. .. .Edged with parallel hairs 

 Cingulate .Spirally ribbed or ridged as in 



Sella adamsi, PI. 38, Fig. 22 

 Cleaning shells.... p. 7 



Close. .. .Bivalve shells which do not gape 

 Columella. .. .The pillar of univalves, portion 



near imaginary axis around which shell re- 

 volves 

 Compressed Flattened laterally; a reduced or • 



contracted aperture as in Distorsio, PI. 42, 



Fig. 8 

 Concave. .. .Hollow, opposed to convex 

 Concentric lines or ribs. .. .Lines which follow, 



more or less, the margin of bivalve shells, 



p. 17 

 Conchyolln. . . .p. 12 

 Conic. .. .Shape of a cone 

 Conical aperture Sloping from center as in 



Dladora, PI. 30, Fig. 5 



Cordate. Heart-shaped 



Coronated. .. .Crowned; spines encircling the 



whorls as in Melongena, PI. 48, Fig. la 

 Costated. . . .Ribbed 

 Crenulated. .. .Scalloped at margin; saw-toothed, 



often the result of line terminations; see 



Pisania, PI. 47, Fig. 5 

 Cretaceous. .. .Shell with a large proportion of 



calcareous matter 

 Cuspidate. .. .Prickly pointed 

 Cyclodont Hinge teeth arched, see Fig. 22, 



p. 16 

 Cylindrical. .. .Transverse diameters somewhat 



equal as in Oliva 



Dead shell. .. .More or less worn, lacking origi- 

 nal finish; without the living animal 



Decapoda. . . .p. 148 



Decollated. .. .Apex broken off, p. 13 



Decussated .Striae (or sculpture) which cross 



each other at acute angles; sometimes forming 

 hollows as in Nassarlus trivittatus, PI. 46, 

 Fig. 10 



Deflected. .. .Bent backward or to one side 



Denticles. .. .Hinge teeth, p. 16 



Denticulate. . . .Toothed 



Dental formula. .. .Reference to radula, p. 18 



Dentated. . . .Toothed 



Denuded. Destitute of covering 



Depressed Spire only slightly elevated above 



body whorl 



Dextral. . . .Right-handed 



Diaphanous. .. .Transparent, clear, pellucid 



Dibranchiata. . . .p. 148 



Discoidal. .. .Revolving nearly in the same plane, 

 resembling a disk 



Disconnected. .. .Tube separated as in Spirula, 

 PI. 28, Fig. 6 



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