612 P. HERBERT CARPENTER. 



no doubt whatever as to the connection of its cavities with 

 those of the chambered organ, and through it, with the vas- 

 cular axis of the stem in stalked Crinoids. Ludwig ^ has 

 given excellent figures in illustration of these points ; and my 

 own observations have repeatedly demonstrated their accuracy, 

 not only in Ant. rosacea, but in other genera and species. 

 The chambered organ is an enlargement at the top of the 

 vascular axis of the larval stem, which Perrier describes as 

 continuous with the ovoid gland. But he nowhere mentions 

 the vessels contained in this axis which expand into the 

 cavities of the chambered organ above, just as in the stalked 

 Crinoids; and he does not appear to consider these chambers as 

 part of any blood-vascular system. If, as he seems to imply, 

 they are disconnected from the ovoid gland in the adult, how 

 does he explain the connection of the latter with the axis of 

 the larval stem ? 



It will be noted that Prof. Perrier tacitly admits the con- 

 nection of apparently vascular structures with the ovoid gland, 

 though he speaks of them as its ramifications and as seemingly 

 blind. I am well aware of their apparent blindness, but it is 

 simply due to the impossibility of any single section showing 

 more than a very small portion of their winding course. This 

 is a difficulty familiar to all workers. But a careful study of a 

 good dissection, or of a moderately thick transparent section, 

 especially with a binocular, or an accurate plotting out on 

 paper of a series of thin sections by means of a camera, will 

 reveal much that is totally unrecognisable in other ways. The 

 diagrammatic figures which I have given of transverse and 

 longitudinal sections through the disc of Actinometra^ were 

 made by thus plotting out with a camera. 



The intervisceral blood-vessels of this and other types have 

 no glandular structure whatever, as they should on Professor 

 Perrier's theory. They are simple tubes as described by 

 Ludwig, and lined by an epithelium which is more delicate 

 than that within the extensions of the body-cavity into the 



1 ' Zoitschr. f. wiss. Zool., Hd. xxviii, Taf. xiv — xviii. 



2 Tliis Journal, vol. xxi, PI. xii, figs. 1 !•, 15. 



