CLASS AMPHINEURA 



The Amphlneura are one of the five 

 primary divisions of the Mollusca and in 

 many respects the most primitive of all. 



The Chiton consists of eight 

 plates bound together by a leathery girdle 

 of connecting tissue. Fig. 29 shows the 

 details of the plates. 



They are bilaterally symmetrical; 

 the anus is posterior and median; the head 

 without tentacles or eyes. Upon the out- 

 side or dorsal surface, of certain species, 

 are minute black eyes in great numbers 

 which appear to refract light. 



They may 

 be sought for on 

 all except sandy 

 coasts. Some are 

 found upon rocks 

 at or near high 

 tide, others be- 

 tween tides and 

 at varying depths 

 clinging to shells, 

 stones or solid 

 objects. A blunt 

 knife is useful 

 in detaching them 

 from rocks. They 

 should be tied 

 to a flat stick, 

 after capture, to 

 prevent curling 

 and bound with 

 soft twine. This 

 will support them 

 until the tissues 

 are relaxed when 

 they may be placed 

 in alcohol. As 

 an alternative 

 they may be boiled and the soft parts re- 

 moved but in the tropics it is better to 

 preserve them in spirit. 



The descriptions and illustrations 

 covering the coat-of-mail shells are large- 

 ly derived from Pilsbry's work in the Man- 

 ual of Conchology. 



Fig. 29 

 Plates of Chiton 

 First, fourth, and eighth 

 valves of a Chiton, showing 

 1.1, laminae of insertion; 

 n, n, notches; s.l, s.l, 

 Butural laminae. X2 



ORDER POLYPLACOPHORA 



Family Lepidopleuridae 



GENUS LEPIDOCHITON Gray 1821 

 (PRETTY CHITONS) 



LEPIDOCHITON ALBA Llnne. White Chiton. 

 Shell small, under a microscope the sur- 

 face beautifully granulated, covered with 

 bluish-black color which easily rubs off; 

 valves slightly keeled, a feeble ridge of- 

 ten dividing each side into two triangles; 

 about twelve marginal teeth upon anterior 

 valve; margin yellowish,' membranous and 

 with beaded granules as a covering. Length 

 15 mm. Range in depth 1-337 fathoms. 



PI. 56, Fig. 3 



Greenland to Massachusetts Bay 



LEPIDOCHITON MARMOREA Fabriclus. Marbled 

 Chiton. Shell brownish or yellowish -red 

 variegated with angular whitish lines, also 

 whitish points along the posterior edge of 

 valves, minute granules upon surface, mar- 

 gin pubescent (hairy) . Length 35 mm. 



PI. 56, Fig. 7 



Greenland to Massachusetts; Cir- 



cumboreal 



LEPIDOCHITON RUBER Lowe. Red Chiton. 

 Shell small, oval, keeled, elevated lines 

 of growth visible upon valves; light brick- 

 red or flesh color with streaks of crimson 

 upon one or more valves, often incrusted 

 with a black foreign substance; margin with 

 red and white dus* rranged In alternate 

 stripes; interior bright red. Length 20fflm. 



Found mostly adhering to stones, 

 1-80 fathoms. 



PI. 56, Fig. 8 



PI. 70, Fig. 9 



Labrador to Connecticut; Clrcum- 



boreal 



22 



