oil LITTLE-KNOWN COMATUL^. 515 



A syzygy in the third brachials*, and another about the eleventh 

 joint; then an interval of 3-5 joints between successive syzygia. 



The first pair of pinnules are borne by the epizygals of the 

 two lowest gyzygial joints. They are about equal in length 

 (20 mm.), and consist of about 40 joints, the lowest five or six of 

 which are wide and stout, with prominent dorsal edges but no 

 distinct keels. The next two pinnules on either side are of de- 

 creasing length and stoutness, the second and third joints being 

 wide, with strong and expanded dorsal keels. The fourth pair, 

 though somewhat shorter than the third, are considerably stouter, 

 with wider and more massive joints and largo genital glands. 

 The following ones somewhat longer and tolerably equal, de- 

 creasing again after about the 25th joint, but remaining stiff 

 throughout and never becoming specially slender. The lower and 

 middle joints of these pinnules, till far out on the arms, are very 

 wide (reaching nearly 2 mm.), with sharpened dorsal edges. The 

 middle joints of the pinnules do not become elongated till about 

 the 80th arm-joint. Terminal comb limited to the first three 

 pairs. 



Disk naked, 15 mm. in diameter, with a radial mouth. Colour 

 brownish white, with a broad reddish-brown band on either side 

 of a nai'row ligliter one in the median line of each nrm. 



Spread about 30 centim. 



One specimen from Hongkong. 



Bemarlcs. — The fine specimen described above is one of many 

 variations on the type of Comatida solan's, Lam., one of the 

 species for which the genus Actinometravax^ originally created by 

 Miiller. Lamarck's examples were obtained in the Australian seas 

 during the voyage of Peron and Lesueur (1803) ; and they were 

 subsequently examined by Midler, whose description of them is 



" In this species and its allies the two outer radials and the two lower 

 brachials are united by syzygy, so that the true third brachial appears to be 

 the second. This joint itself is primitively double, consisting of the orighial 

 third and fourth brachials, which are united by syzygy, tlie pinnule on the third 

 joint remaining undeveloped. There are very few Comaiulie (e. g. Actinonietra 

 '/iuUtimdiaia) in which this is not tlie case ; and it is therefore convenient to 

 speak of the third brachial as a syzygial or double jouit. But the rare syzygial 

 union of the first two brachials, as in Act. solaria, is of a different morphological 

 value altogether; and it is therefore better for the purposes of description to 

 consider them as really two joints, rather than as forming a single compound 

 one. In most Comatida they are united by a ligamentous articulation, which 

 has often been wi'ongly spoken of as a syzygy. 



