30 ON THE ECHINODERMATA OF THE 



to each adambulacral plate, owing to the plates which bear the spines being more widely 

 spaced. The abactinal body-frame is formed of transverse bands of ossicles ; and these 

 are packed closely together in longitudinal series along the ray : the plates are very 

 uniform in size ; and as each generally stands opposed to a corresponding plate in the 

 neighbouring transverse row, a fairly regular rectilinear arrangement is the result. The 

 median ossicles, which are somewhat larger than the rest, imbricate upon one another 

 and form a distinct line along the ray. The membranous interspaces are of moderate size 

 and punctured with one or two papulae. Each ossicle bears a small subquadrate group 

 of from three to five short dorsal spines, amongst them being placed two or three of the 

 pedicellarise forcipiformes, but which are somewhat more numerous towards the sides of 

 the ray. The spine-groups, in consequence of the regularity of the network, are disposed 

 in longitudinal and transverse lines, those of the middle row being rather larger and more 

 densely packed than the others, and thereby forming a more or less distinct medinn 

 line down each ray. From the apices of the spines, which are broader than the bases, 

 proceed three or four small denticles ; and the spinelets being all of equal length and 

 closely set, give a smooth velvet appearance to the Starfish. Pedicellarise forficiformes 

 are found along the margins of the ambulacral furrow at intervals of every two or three 

 plates, but are comparatively small in size, short, and somewhat rounded or obtuse at the 

 points. Two or three larger ones are frequently met with in the neighbourhood of the 

 actinostome, often quite gigantic ; and a few isolated individuals also occur on the dorsal 

 surface, but seldom beyond the base of the rays ; these, it need scarcely be said, are 

 considerably larger than the p. forcipiformes which accompany the spine-groups above 

 mentioned. The p. forcipiformes that occur on the lateral portions of the rays are, as 

 a rule, situate on the aboral or outward side of the spines. The madreporiform body 

 is situated near the margin, and is large, simple (having but few stria?), and surrounded 

 by a circlet of the dorsal spines. 



Size. This species seldom measures more than from one inch to an inch and a 

 half in diameter, and is generally less. A variety, noted below, is recorded from 

 Eastport 4 inches in diameter. 



Colour. In a living state Stichaster albulus is described as of a faint red or 

 cream-colour. When dried, or in spirit, it is usually light yellow, varying to more or 

 less warm shades of light brown. 



Habitat. On stony ground and Laminaria in 5-20 fathoms, and seldom in greater 

 depths (OlriJc). It has been taken by Barrett in from 3-25 fathoms, also on stony 

 ground (LiitJcen, 1. c. p. 30). Verrill similarly records its occurrence on the coast of 

 Maine and Grand Manan, in 10-20 fathoms, on rocky bottoms and among Nullipores, 

 and frequent also at low water of spring-tides among rocks (1. c. p. 351). Stimpson 

 states that at Grand Manan the species occurred most frequently among branching 

 Nullipores in 4 or 5 fathoms on the east side of the island. 



Variations. Although the number of rays in this species is almost invariably six, 

 about two per cent, of the specimens collected have only five, according to Stimpson's 

 observations at Grand Manan; and examples with seven occur occasionally. The same 

 authority also records that four out of five had three of the rays much larger than the 

 others. 



