ABTEBOIDBA 01 NORTH PACIFN *M> aJMACSNI WATERS FISHER 



117 



fr>>m la 1 in tlmt Um dorsolateral plltW carry ODC M two rather than tWO ">r tl 



\\ ■ atever factors reduce the number of superomargina] spinelet Inal. 



I -. , . iiui-iis. K 20 to R 15 mm., including two or tl 

 rayed, more robust rpecdmena U Dd to have less, regular abaetti 



. limn- l{ i.'i mm to R 26 mm and from quite Minder It J I mm bi B.6mm i lly 



plump ilt 28 mm.; i>r. 7.5 mm i rays; doraolateral spineleta usually aolitary. B 

 these are probably young la 1 , without the a. lull, full complement "f 

 milar to lo*, iplnea varying In >•< | rays medium i 



.uncus, K 22 mni. t.i 12 mm. Two other Intermediate betwi i a* 



iiml with lubeapitate, ipaoed ipinelel i than in <>' resemble /■ eomfaefcoi I' 



• r .:t, tic 5.) 



Ill Superomarginal spineleta two, sporadically three; dorsolateral platea with 



usually solitary Bpinelets, us n consequence of which tin' Bpinelets appear well spa 

 oarinals with usually two in three apineleta; inferomarginalfl usually one, boo rad- 

 ically two. 



o 1 . Iii the most regular examples, there are two longiai riea "f solitary, ipaoi d, di 

 on either side of the carina] series "f plates, which carrj threi 



abactinal longiseries "f small papular arei '■ ipeoimeni R 28 mm to R 12 mm, 

 ■lender t.. medium rob B 1 nun. to K 28 mm . slender I 



\ onaiderable Dumber >>f these an' evidently young of Ha', or oven la'. P 



a'. Al'iu-tmal apineleta not in evident longiseries. Three variants are ahown (PI . r >:i, in 



the long rayi of wneotuMri bul the abaetinal spineleta are arranged muc 

 in /.. hexaetit forma rapuIarM, and many of the superomarginals are monaeanthid 1 



I two smaller similar ones are Intermediate in oppi letween md 



resvioris, but whether biologically so I am unable t" Bay. five specimens, K 80 mm to K 

 G I mm. The largeel has somewhat swollen rays and three or f"ur spineleta on ■ few su] 

 marginalt There la a sliRht Indication of serial arrangemeni of abactinal sptnelel 

 ta Figure 7 (lateral parts of abactinal ai i Straig tp< Bgured (PI. 44, fig. 8 



In the foregoing enumeration of variations there is a pretty comp bs of 



gradations from forms 11I" ; • which are difficult to separate from L. Ac 



and others, Ella', which appear tu he intermediate with f to one 



which can easily be differentiated on the basis of three <>r four Buperomarginals II 

 This in turn passes without hiaius into typical vaneotueri (la 1 ) which resembles 

 large, coarse Bpined aeqvalis and is therefore quite distinct from Class HI 



In Class II there is a deviation toward the small variety of /- !•■ rma 



plena with which the type of hexactie shows .lose relationship. 



If large specimens of vancouceri are placed aide 1>> aide with aequalia they may 

 be told at a glance: vancouveri hi r, less numerous abactinal Bpinelel 



daily on the carinals). If the small phase, ,.r young, of Class II is also the y< 

 of [a, then the difference is even more marked, since the young of lo, from having 

 conspicuously fewer spineleta, are quite unlike the young of at In this 



the similarly between the adults of atqvalit and poneoueeH would result from 

 convt 



The mouth plates do tot offer any help. The act liioslonual spine IS 

 lone; „s plate and usually has a small lateral companion 



Madreporic body conspicuous, about mid r I I pedicellariae fairly 



abundant, in circlets around the abactinal and super arginal apineleta. Thej 



not particularly diagnostic, the enlarged tooth on outer side of lip being sometimes 



