1888.] NATURAL SCIENCES OF PHILADELPHIA. 379 



Carpenter in his paper on Crotalocrinus^ explains that "the calyx is 

 broken across near the level of the top of the basals, so that the inter- 

 nal faces of the radials and the following plates are exposed to view, 

 with the remai-kable striations upon them, which were regarded by 

 Angelin as corresponding to the consolidating apparatus of Cupress- 

 ocrinus," and he proceeds : "It is possible that, like this structure, 

 they may represent an uneven surface for the attachment of muscles 

 and ligaments, but whatever else they may be, the strise are certain- 

 ly not hydrospire slits, as supposed by Wachsmuth and Springer in 

 1879 **=!<*. But in any case they will no longer be able to re- 

 fer to this family as Palpeocrinoids which 'probably have hydro- 

 spires within the calyx,' and to use this supposed fact as an illustra- 

 tion of their theory that Blastoids, Cystids and Crinoids are so close- 

 ly linked together that they are not entitled to rank as Classes of 

 Echiuoderms equivalent to the Urchins and Starfishes." 



We have been able to study the organs in question in our speci- 

 men from Gothland (PI. XIX, fig. 1), and in two of those used by 

 Angelin, loaned to us from the National Museum of Stockholm, in 

 all of which they are very well shown. They are totally diflferent 

 structures from the so-called consolidating apparatus of Gupresso- 

 crinus, which we regard as muscle plates for the attachment of 

 muscles and ligaments to move its huge arms. The muscle plates 

 of Cupressocrinus are appendages of the first radials, and form part 

 of the upper surface of the vault, similar to the muscle plates of 

 Symbathocrimis, in which we know from direct observation that they 

 constitute parts of the vault, only the central space being closed by 

 additional plates. In both genera those plates are apposed by cor- 

 responding faces upon the first brachials, and there is no roof or 

 covering of any kind above them, they being necessarily external if 

 they served for places of nuiseular attachment to move the arms. 

 The case is totally different in Crotalocrinus in which the parts in 

 question are roofed over by very solid covering plates, leaving little 

 more than the faces forming the lanceolate areas exposed. Angelin 

 applies the name "consolidating apparatus" not only to the over- 

 hanging margins of the radials, but also to the lamellae under- 

 neath, to which Carpenter refers as "remarkable striations," possi- 

 bly for "the attachment of muscles and ligaments." These so-call- 

 ed striations consist of parallel lamellose walls or partitions, located 

 in regular sets within chambers or recesses, Avhich underlie partly 



1 Op. cit, p. 406. 



