363 



ments. We readily detected them in the dredge, even when obscured 

 with mud, by their clinging to the fingers, as described by Bsch- 

 Bcholtz. 



In some examples the anchors axe very few, and ranged in a double 

 line along the muscular bands. They vary from about twenty-fire 

 in the field of the inch object-glass to three times thai Dumber. 

 Their length averages about the /...th of an inch. The anchor- 

 flukes are sometimes plain, and sometimes barbed with three to fire 

 venations (figs. G-l(i). The anchor-plates are oval and leaf-shaped, 

 having a process (or stalk) at the end to which the anchor is articu- 

 lated ; the disk is perforated by four large simple boles surrounded 

 by an irregular series of smaller openings ; the articular process bas 

 a -lit like the eye of a needle (fig. I.")). In the northern specimens 

 these plates are rounded and rather " obcordate," but in those from 

 the southern locality they are longer, less regular, and somewhat 

 contracted in the middle ; the perforations also are larger in propor- 

 tion, and more angular. 



Some specimens possess a few great anchors, four times as long as 

 the rest, and with large flukes, lying with great regularity in the 

 interspace of the muscular bands ; their plates are correspondingly 

 large, and irregular in outline (fig. 16). 



All the anchors are fixed transversely to the length of the animal, 

 some being turned one way and some the other. 



Besides these, the skin contains innumerable smaller particles, or 

 miliary plates, winch are especially crowded over the muscular bands. 

 They are oblong, or hour-glass shaped, and about \t\\ to £th the 

 length of the anchor-plates, or from yyVo 1 " to FiVij tn of an inch 

 long (fig. 17). 



By far the greater number of the anchors are imbedded in the 

 -kin ; only a few rise above the surface or swing freely on their 

 pivots. They are developed beneath the epidermis, become liberated 

 by the wearing of the surface, and are themselves broken by use and 

 worn away and replaced by others. The anchors are developed 

 before the anchor-plates. First, we find a simple, slender spiculum 

 (tig. 1); then another (fig. 2), longer and expanded at one end; 

 those only which have attained their full length begin to develope 

 flukes (figs. 4, .">) ; and it is not until the anchors are completely 

 grown that we detect any trace of the anchor-plate. This also i 



ppearance as a Straight needle lying beneath the middle of the 

 shank ; in the next .stage it is forked at each cud ; these branches 

 ROW and divide again, until the plate is all sketched out, the margin 

 being added last, and the whole becoming more solid (figs. 7-1 I). 

 We have not met with any figure of tin' spicula of s '. digitata, 



cept the had one given by Midler, whose work we ha\e Ottlj 



able to see in the Library of the Museum of Practical Geol 



Si N \ri v i mi i kins ( BOLOTBTORI \>. ' > 1''. .Midler. I I'l. \ I \ 

 .18-22.) 



The -ceo, ul European St/nai I itiansand, 



on the coasl oi Norway, and figured and described in the 'Z 



