1S(J ACTINLK OV AM5A'l'ia)SS K.X l'l,( »1JAI'U)XS M'MUK'KICll. 



ill (ho ujnuM' |»:ii(. ill some forms ;il lc;ist ; I lie iimscli' lilircs and Mici 

 CJivities instead (if bciiis;' cul across l»y :i I raiis\ cisc- soction llii()u<j,li 

 the nuisclc, fii\o the appcnraiwc ol" boiiii;- cut ]»arallcl to llicir course 

 (IM. XXX, V\iX. ST) and I lie sect ion lias t lie ai>]»earaiice of a horizontal or 

 transverse sect ion tlironuh the upper pa it of the coin inn wall, i'^iirtlicr- 

 more, the cuAities, hianehiiii;' and aiiast»tinosinu' with each other, pass 

 toward the ectodermal surface (»f the mesonhe;), ;iiid ap]>arenlly in 

 soiiu' east's come into contact with llie ectoderm. This ariaiiiicmeiit, 

 as 1 have said, is not so distinct in some specimens as in ollieis, hiil is 

 more or l*'ss marked in all my pre|>aralioiis. 



The tentacles arc ninety-six in nmiiber and are arranged in live 

 cycles, 'i'lu'y are rather short , hut slender and jxiintcd. .\t the outer 

 surface of (lie base of each there is a bulbous swelling' ( 1*1. \\x, l''i<;'. 8!l), 

 I'ormcd principally of thicUened mesonhca (IM. \\\i, b'iii.lM). Theeeto- 

 dernial museulalure, both of the teiitach's and of the disc, is rather 

 weak, the mesonheal ])rocess tor its supixnt l>ein,<i" only slinhlly dc- 

 veloi)i'd. 



The st(unat()da'um is loiiii, exleiidinu', in tiie contracted specimens, 

 almost to the base. It has tw'o siphoiio^ly])hes, \\hieli are well devel 

 oped though not i)artieularly deep. 



There are. twenty-four ])airs (»f niesenierii's arranged in four cycles. 

 Only the six mesenterial ]>airs of the lirst cycle are perfect. The 

 mesenteries of the second cycle, though imperleet, resemble (lu>seot 

 the lirst cycle in bein,u' nonpuioplunic, the reproductive origans being 

 borne alto«jelher by the mesenteries ol the thirtl (IM. xxxi, Fiy. \H)) and 

 fourth cycles. In the r(\i»ioii of the mesentery occupied by the icpro- 

 diictive elements in femah' individuals the meso^hea is ore;i||y eulari;etl 

 ( ri. XWl, I'ii;-. *.H)). the ova (o/) beiiiy imbedded in t he eidar^cment. 

 This does not occur in the iiiesenteiies of male indi\iduals from the 

 .Vtlanlic coast of North America; all the Allxtlro.ss s]>eeinieiis I ex- 

 amined tor this point proM'd to [»e females. The lonnit ndiiial muscles of 

 the mesenteries are not particularly well dcNclttpcd (1*1. \\\l, I'^ii;. 1>2), 

 and there isnocircumscril)e<l pennon. The low meso^lo'al processes (end 

 somewhat to be arraiiiiCil in Itiinclics of a few arisiii<;' from a common 

 basis. At the bases of the mesenteries, /. c, at their attachment to the 

 colunin, there is a \vell marked pinnate ]»arietal muscle. 'I'he acontia 

 arc not abundant. 



ISo. 7.">4, as stated above, dilVers in s(Hue respects from No. TlL'. its 

 base is not deeply eonca\e as it is in >i«). 7I-, nor «loes it seem to 

 have inclosed mud or sand tor an aiiclKU', but appears to have been ad- 

 herent. The InlM'rch's of the e(dumii are somewhat more distinct and 

 rounded than in No. 712, and yie all coxered byciilich'. 'IMie s|diincter 

 has essentially the same structure as No. 712, but I did not dissect the 

 si)eeimeii sulhcienlly to determine if the likeness c\t«'ii(U'd to all the 

 parts. I think, liowc\('r. that there is little reason lor disbelieviny; in 

 the specilic identity ot' the spt'ciineii with No. 712. 



