456 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



four times as broad as long with a dorsal tubercle. The IBr! is smooth. There 

 are 10 arms, all broken. P, is 6 mm. long with 9 segments. P 2 is 7.5 mm. long with 

 11 segments. P 3 is 7 mm. long with 9 segments. The centrodorsal is a rather low 

 pointed cone 2 mm. high. The cirri are XV, 56-70, 25-47 mm. long. The short 

 apical cirri have the seventh-fourteenth segments slender, twice as long as broad. 

 The radials are three times as broad as long with a dorsal crest. The 10 arms are 

 about 60 mm. long. The brachials develop dorsal spines from the fiftieth onward. 

 The distal intersyzygial interval is 5-6 muscular articulations. P] is 5.5 mm. long 

 with 10 segments. The distal pinnules are 9.5 mm. long with IS segments which 

 are from two to two and one-half times as long as broad. The centrodorsal is 3.5 

 mm. high. The cirri are XVII, 67-82, 48-62 mm. long. The radials are three times 

 as broad as long, with a dorsal crest. The 11 arms are 85 mm. long. Dorsal spines 

 are developed from the fiftieth brachial onward. The distal intersyzygial interval 

 is 6-9 muscular articulations. P, is 5.5 mm. long with 11 segments. P 2 is 7 mm. 

 long with 12 segments. P 3 is 6.2 mm. long with 9 segments. The distal pinnules 

 are 10 mm. long with 18 segments which are from two to two and one-half times as 

 long as broad. 



In the specimen from the Sahul Bank, which was described as a new species 

 under the name of Asterometra acerba, the cirri are XX, 84-90, 55 mm. long, more 

 slender than those of the type specimen of A. anthus. The radials have a moderately 

 prominent dorsoventrally elongated median tubercle. The elements of the IBr series 

 have a faint narrow low median carination. The 10 arms are 80 mm. long, slightly 

 more slender than those of the type specimen of A. anthus, with slightly longer 

 brachials. The arms are distally strongly compressed laterally, but the overlapping 

 dorsal spines are not nearly so long or so stout as in the type of A. anthus. The 

 pinnules are much longer than those of the type of A. anthus and more slender, with 

 proportionately longer segments which terminally are three times as long as broad 

 or even longer; in the type of A. anthus the length does not exceed twice the width. 

 PI is 7 mm. long with 12 segments. P 2 is similar, 7.5 mm. long. P 3 is 8 mm. long, 

 slightly stouter than P 2 . P 6 is 9 mm. long. The distal pinnules are 13 mm. long. 



Gisle'n noted that the carinate process on the radials is more distinct in young 

 than in full-grown individuals because in them the radials are longer. With increas- 

 ing age the radials become more and more concealed by the centrodorsal, and are also 

 shortened by the rapid increase in width. Correlatively, the carinate process grows 

 smaller and finally remains only as a rounded tubercle. He said that in the very 

 young specimens examined by him one can plainly follow the shortening of all the 

 ossicles during growth already observed by P. H. Carpenter. Perhaps this is best 

 shown in the proportions of the cirrus segments, but it is also well seen in the radials 

 and proximal brachials. In the brachials also one can follow the disappearance of 

 the juvenile carination on the first two, and the appearance of certain indications of 

 old age, such as the indistinct carination on the same ossicles in certain old specimens. 

 The pinnule segments seem to be but slightly affected. 



The occurrence of orals is also very interesting. In specimens with an arm 

 length of less than 10 mm. they are well preserved, but they usually begin to be 

 resorbed at an arm length of 10-12 mm. and are completely lost when the arm length 

 reaches 15 mm. that is, at about the time the pinnulation is complete. 



