aJBTEROIDHA Of WORTH PACIFIC IND LDJACEN1 w \ i i , - PI8B0BB It" 



medium •■. but I have seen do | imen K 208 nun . 



r 27 inm. \>r. 34 nun 



It is not possible to describe this forms with any d 

 principa] variants will be indicated l>y means of fig 



I In li- moel generalized phase this forms maj be descrih pined 

 Ihostoma, the spines being short, Bubequal, and defining a reticulum, (PI 



i | This variation intergrades with er and thick- 



rayed specimens and considerable range in the number and caliber of the -pin. 

 Clayoquat Sound, Departure Bay, Gabriola Inlet, British Columbia; Straits of Fuca, 



Juan Islands, Wash.; Monterej Bay, t'alif. 



II The increase ^t.-m 1 1\ in number and i «ne fairly packed on the 



carina! and dorsolateral plates, the papular areas becoming smaller. I'l ■ 



These multispined forms intergrade with I: and a Bimilar variation in • 

 thostoma differs only in having smaller Bpinee and usually more numerous supero- 

 marfriiutl Bpines. Fori Rupert and Departure Hay. British Columbia; I 

 Alaska; Monterey Bay, Calif. 



(Ill Disp irity in the size of the spines gradually increases from a slight diffen 

 as in plate 62, figure I. through a series: Plate 61 . figure _': plate 62, figure 2, 3 . plate 

 61, figure 3 and pint •• 60, figure 3, wliirh have the spines as unequal as forma '■ 

 Plate 60, figure 3, may be classed as an aberrant troscheHi, or as an intergrade. 

 Unalaaka to P 3 iund. 



IV Acervation <>f the major dorsal Bpines is developed in vario 

 sliplit to very prominent (pi. ♦">_? . li_r- I. 3; i>1 63, tiu r 3). Departure Hay and Bayne 

 mbia; Puget Sound. 



Bach of the above varies as to length and breadth of ray: that is, each variety 



longer and shorter as well as slenderer and thicker rayed representatives. I 

 intergrades with II. III. and IV: II and IV intergrade; III and IV intergrade. 



In forms alveolata the abactinal spines are individually very similar to those of 

 forma tretehelii. They vary from cylindrical truncate, through clavate forms 

 capitate, a little higher than broad to broader than high; and from capitate to a 

 curious flaring obconic form with a convex summit broader than the height. P 

 Sound, Departure Bay, pi. 62, ti'_' 2 > The summit of the Bpines is finely sti 

 The smaller striate, are cylindrical to clavate, obtuse to truncate, with 



r certain Dumber slightly tapered and bluntly pointed When there is disparity 

 in the size of the 'i"' sal spines the -mailer are usually more numerous, stand in Btraight 

 orsag a the trabeculae and outline th< il intervi ivier 



Bpines form a pretty definite carina! series either singly or in groups, and dorsolater* 

 ally occupy singly or in groups of three to five) the principal nodal points of the 

 skeleton. Prom the formation of groups (pi 62, fig i it is only a step to an i 



condition IV, ab 



Specimens from Unalaska havi tically few major spines but numi 



much smaller minor .-pin. PI. 61, fig. 2; pi. I mm 



aeafUhottoma witl pines sprinkled over the surface, but the sup. 



marginals are mostly monacanthid They differ froi Hi in their more numci 



■>dary -\> > reticula nt. 



