MUSEUM OF COMPAKATIVE ZOOLOGY. 123 



what colored on the inside. In that respect it is not quite like the 

 bursa of most Ophiurans, which is composed of the lining membrane, or 

 layer, of the body-wall. 



The spermatozoa of Ophiocreas oedipus after their long immei-sion in 

 alcohol, were doubtless much altered. Strongly magnified, they resem- 

 bled little translucent grains of boiled sago, but showed no projection or 

 ciliary tail. 



In Fig. 7 the floor of the stomach, St, St, is slit to expose the sper- 

 matic pouch, so that the lower portion is separated from the upper one, 

 which lies under the radial shield, /, and whose roof grows closely to the 

 disk-wall, as in Astrophytons. It also adheres, as mentioned above, to 

 the iuterbrachial floor of the disk-wall. Indeed, it is scarcely free at 

 any point save a space along the top of the arm, which forms an oblong 

 sinus. The interior of the stomach is lightly marked by radiating 

 pleats, and there are also five pairs of strong radiating ridges, a pair over 

 each arm, which form partial partitions. 



These brief observations show that Astrocnida, and behind it Astro- 

 gomphus, is nearest in relationship to the true Astrophytons. Not only 

 does the arm-covering, with its double rings of minute hooks, shadow 

 forth an affinity, but the internal structure, with a pouched stomach, 

 and ovaries lying free in the general body-cavity, is similar ; while the 

 want of adhesions on the under side of the stomach and the closed ring- 

 tube about the mouth remind us of the Ophiurans. But, in reaching 

 after some form which may bridge the way to these last, we find, as gen- 

 erally happens in the animal kingdom, no piece that will fit. Ophio- 

 creas, which is properly a simple-armed Astrophyton, is not intermediate. 

 It is a synthetic form. It has the teeth of Euryale, the pleated stomach 

 suggestive of Gorgonocephalus, the genital bm-sa and ovarial tubes sim- 

 ilar to, yet not the same as, those of Ophiurans in general, the arm-plates 

 that recall Ophiomyxa ; nay, one Astrophyton character, the adhesion 

 of the stomach to the disk-wall, is carried faither than in Astrophyton 

 itself. 



In conclusion, it is proper to suggest a slight resemblance which the 

 branching Astrophytidne have to the order of Starfishes. This is in the 

 stomach-pouches filled with a clotted matter, which suggest the varied 

 ca'cal appendages characteristic of difiereut genera among Asteroidea. 



