MONOGRAPH OF THE EXISTING CRINOIDS. 527 



Bury gives the length of the free-swimming larval life as about 12 hours. 



Barrois states that the embryo usually remains inclosed in its membrane and 

 attached to the pinnule of the parent until the sixth or seventh day, and that the 

 majority are not freed until the seventh day, though in this respect they are 

 subject to considerable variations. Elsewhere he says that the duration of the 

 development of the larvae is seven days of 24 hours each. 



He also noticed that many larvae continued for a considerable time without 

 fixation and then underwent abnormal development. 



ANTEDON ADRIATICA. 



The pentacrinoids of this species are almost identical with those of Antedon 

 mediterranea. 



There are usually five infrabasals. 

 The columnals number 13-18. 



COMPSOMETRA SERRATA. 



While staying at Misaki, Japan, Doctor Mortensen was so fortunate as to 

 obtain a large series of the pentacrinoids of this species, upon which he is now 

 working. 



Up to the time of Mortensen's visit to Japan Compsometra serrata was known 

 from only two specimens, both taken in the same dredge haul by Mr. Alan Owston. 



COMPSOMETRA LOVENI. 



Part 1, fig. 410, p. 317. 



There are at hand, attached to a small piece of seaweed from Port Jackson, 

 New South Wales, four very young pentacrinoids of this species, in none of which 

 the radial structures have as yet appeared. 



The length of the most developed is 2 mm. 



The column is composed of 14 columnals, with in all cases an irregularly 

 lobate terminal stem plate, which is rather large. The first four columnals are 

 very short, lenticular, the first the shortest. The following increase in length 

 to the seventh-eleventh, which are about three times as long as broad, with the 

 median annulus very prominent; the distalmost become shorter again. 



The basal cup is broader than high, with the profile strongly rounded. 



The orals are about as long as the basals, with the distal portion strongly 

 incurved. In the proximal half the sides are parallel; in the distal half the 

 outline is semicircular. The central portion, a triangular region with the proximal 

 border as a base, is depressed, the lateral areas beyond curving rather strongly 

 outward. 



In the smallest specimen the orals, which are narrow, are only slightly 

 depressed in the middle, the eversion of the sides having only begun. 



Judging from the figures given by Wright of his new genus and species 

 of sponge, Kallfepongia archfri, it was based chiefly upon a pentacrinoid of 

 this species. 



