440 THE CANADIAN NATURALIST. [DeC. 



observed passing through the walls of this organ in this species, 

 in which it appears to be more than usually dense. 



In another specimen in Mr Wachsmuth's collection, apparently 

 of Actinocrinus proboscidialis, this organ, as seen with one or 

 more of the outer turns removed, has an oval or sub-elliptic form, 

 being contracted and twisted at both ends, so as to present very 

 nearly the appearance of the shell of some species of Ovulum. Its 

 walls are quite thin, and seem to form more convolutions than 

 in any other species in which we have had an opportunity to 

 examine it. As seen by the aid of a magnifier by transmitted 

 light, it presents a very beautiful appearance, being composed of a 

 great number of minute pieces, with numerous openings passing 

 through between them. The little pieces and the openings 

 between them, are of nearly uniform size, and arranged so that 

 there are usually one or two of the former intervening between 

 any two of the openings. 



Another of Mr. Wachsmuth's specimens oi Actinocrinus sccurus, 

 Hall, has one side of the body removed so as to show about two- 

 thirds of the convoluted organ, the upper part of which is broken 

 away. The part remaining has a short wide sub-cylindrical form, 

 with a rather broad, obliquely truncated lower end, which is not 

 tapering, as in the other species. Under a magnifier it is seen to 

 be composed of an extremely fine net-work, far surpassing, indeed, 

 in delicacy of structure, the finest laces that it is perhaps within 

 the power of human skill to fabricate ; and as it is entirely free 

 from any surrounding matrix, excepting at one side below, the 

 specimen has to be handled with great care, as a mere touch of 

 this delicate part would probably cause it to fall into hundreds of 

 little minute fragments. On examining it under a magnifier, the 

 bars of which it is composed are seen not to intersect each other 

 at any uniform angle, but anastomose, so as to impart a kind of 

 irregular regularity, if we may so speak, to the form and size of 

 the meshes. Of these little bars there are two sizes, the larger 

 forming the larger meshes, while within the latter a smaller 

 set of processes extend partly or entirely across, so as to form 

 more minute meshes ; the whole presenting a beautiful appearance, 

 of whiee it would be difficult to convey a correct idea by a mere 

 description alone, without the aid of figures. 



From analogy, judging from what is known of the internal 

 structure of the recent genus Comatala, in which several authors 

 have noticed a reticulated calcareous structure secreted within 



