MUSEUM OF COMPARATIVE ZOOLOGY. 119 



the body-cavity, and not a closed annular tnbe. It may be seen in 

 wider section in Fig. 2. The main stomach, directly above its own cen- 

 tre, passes upward to the roof of the disk as a simple cone, round which 

 appear the folds of the radiating pouches (Fig. 1). To give a general 

 notion of this complex organ, we may suppose a large loose bag, having 

 a hole at the bottom (mouth), and whose periphery is gathered in nu- 

 merous radiating folds, leaving, within, a central flask-shaped open space 

 communicating directly with these folds ; and, further, that the folds 

 are divided into ten lobes, and each lobe is attached at the bottom by a 

 radiating adhesion. 



The central cavity of the stomach was empty, but its lobes were 

 stuffed with a coagulated, yellowish, pasty substance, which, either sim- 

 ple or with reagents, presented no special structure under the micro- 

 scope, and which contained no organic remains. 



The ovaries consist of deep, lobed and contorted folds of the lining 

 membrane of the disk-wall on its floor, sides, and a portion of its roof. 

 These folds are crammed with egg-clusters, so as to resemble puddings 

 or sausages (Figs. 1 and 3, 8, 8) ; and, whatever their form, all end by ad- 

 hering at their inner margins to the outer ends of the corresponding 

 stomach-pouches, whose basal lines of adhesion they also continue along 

 the arms, and along the median line of each interbrachial space. As 

 has been said before, the body-cavity is thus divided into ten radiating 

 compartments freely communicating at their inner ends by large holes 

 through the partitions. A genital opening enters each of the compart- 

 ments (Fig. 3, Ji o). Gorgonocephalus, therefore, has no closed bursa, 

 with its cluster of genital tubes, but the €7iti7^e hody-caviti/, except the 

 open (perihsemal) ring outside the mouth, is also the genital cavity. It 

 was a similar arrangement that the older anatomists attributed to Ophi- 

 urans ; and it is strange that their observations were true only of genera 

 they had never dissected. 



As to internal composition, the ovarial lobes are uniform, and every- 

 where contain, under a thin, membranous envelope, crowded masses of 

 egg-clusters averaging about 1 mm. in length, and separated from each 

 other by delicate membranous partitions (Fig. 4). The eggs which com- 

 pose each cluster are round, and about | of a mm. in diameter. The 

 general envelope, as may be seen in the figure, becomes thicker at the 

 free margin, and especially so at points where it grows to the stomach- 

 pouches. Its function of supporting the stomach points to its homology 

 with those slender threads that suspend the Ophiuran stomach to the 

 body-wall. I was not able to detect on the surface of the ovarial lobes 



