A MONOGRAPH OF THE EXISTING CRINOIDS 



489 



is by far the stoutest pinnule on the arm; it is 10-17 mm. long and is composed of from 

 14 to more than 30 smooth cylindrical segments. P 8 is very small, and the pinnules 

 following are still smaller. The disk is about 17 mm. in diameter and is deeply 

 incised. 



In 1891 Hartlaub wrote that after repeated comparisons between the specimens 

 that he had described as protecta and the type specimen of Carpenter's imparipinna 

 he had become convinced that the two forms are identical. The type specimen of 

 imparipinna is in a condition very unfavorable for the description of the lower pinnules, 

 because the arms are all bent in over the disk, and it is not surprising that the chief 

 character of the species, the difference in size between the P 2 on the outer and inner 

 arms, escaped Carpenter's notice. Another character of no less importance, the 

 extraordinary smallness of P 3 in comparison with P 2 , was, however, rightly emphasized 

 by Carpenter. 



The two specimens in the Hamburg Museum labeled Tonga and Fiji upon which 

 Hartlaub, in part at least, based his Antedon protecta are both small. 



The three specimens from Tonga in the Berlin Museum, which were received 

 from the Godeffroy Museum, have 40 arms. 



The specimen from New Caledonia has 40 arms. 



The specimen from Ugi, Solomon Islands, is typical with 30 arms about 70 mm. 

 long and the cirri XXII, 24, 15 mm. long. 



The two specimens collected by the Gazelle at Bougainville Island agree perfectly 

 with a series from Singapore in the Zoological Museum at Copenhagen. Each has 

 40 arms and is dark brown in color. 



One of the specimens from Mer, Murray Islands, is the type specimen of Dr. 

 H. L. Clark's Lamprometra brachypecha. He described it as follows: The centrodorsal 

 is large, thick, and flat, 5 mm. in diameter, with the bare dorsal area about 2.5 mm. 

 across. The cirri are XXXVI-XLVI, 22-25, and are distally compressed laterally. 

 All the cirrus segments are broader than long. The distal segments have a very 

 inconspicuous and low longitudinal ridge. The opposing spine is very small. The 

 39-50 arms are 50 to 60 mm. long and 10 to 12 nun. (?) broad distal to the middle. 

 They are notably short and are composed of about 100 brachials. There are no lateral 

 processes and no tubercles. The basal brachials are slightly swollen either in the 

 middle or at the distalmost corner. The first few brachials are nearly quadrate, but 

 those succeeding rapidly become low wedge-shaped, twice as broad as long, and then 

 quadrate again as the tip of the arm is approached. Syzygies occur between brachials 

 3 + 4 and 15 + 16 (or 18 + 19), and distally at intervals of 10 to 20 (usually 11) muscular 

 articulations. The lower pinnules on the outer side of every first and fourth arm are 

 much bigger than any others. PI is usually about 10 to 12 mm. long, with 23 or 24 

 segments, more or less cylindrical and stiff, but somewhat flagellate at the tip. P a is 

 about the same. P 2 is bigger than PI to a greater or less degree, often 13 or 14 mm. 

 long, with 25 segments. P b is similar but smaller. P 3 is very small, not half of P 2 , 

 with 8-11 segments. P c is about the same. The succeeding pinnules gradually be- 

 come longer and at the middle of the arm are 6 to 8 mm. long and composed of 19 or 

 20 segments. All the pinnules are more or less cylindrical and are composed of per- 

 fectly smooth segments. The color in life is bright green, somewhat variegated with 

 brown and white and with a broad band of white crossing each arm distal to the middle. 



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