160 BULLETIN OF THE 



Actinometra pulchella romxALiis sp. 



Cirrhi 15-20, of 15-18 joints ; the fourth or fifth is the longest, and the fol- 

 lowing ones gradually develop a blunt spine on the dorsal side. Two radials 

 only visible ; the axillary short, wide, and almost triangular. lO-iu arms, 

 most of the rays usually dividing twice, the first division (ilistichals) consisting 

 of two joints which are not united by syzygy. Wlien the arms spring directly 

 from the radial axillary, the two lowest brachials are united by ligament, as in 

 most CmnatuliL', and the third is a syzygial or double joint. But in all the 

 arms which spring from a distichal axillary, the two lowest bracliials are united 

 by syzygy to form a double joint ; and the true third brachial, which is also a 

 syzygial joint, as in all Coviaticke, thus becomes the second arm-joint, as in Act. 

 Solaris* The positiijn of the next syzj'gy may be anywhere between the 12th 

 and 20th joints, after which there are usually intervals of three or four joints 

 between the successive syzygia. The lower arm joints are sharply wedge- 

 shaped, alternating from side to side, the later ones gradually becoming blunter. 

 In some specimens the dorsal surface of the arms is unusually smooth, the 

 joints not overlapping in the slightest degree ; but in others the lower parts of 

 the arms, about as far as the 25th joint, are exceedingly rough. The distal 

 edge of each johit is raised on the side next the pinnule into a high, somewhat 

 recurved plate, with more or less serrated edges. This is. largest about the 

 15th joint and gradually decreases in prominence, the joints after the mieldle of 

 the arm being (|uite smooth. f The arms of most individuals, whether rough 

 or smooth, are bordered throughout their whole length by a lateral expansion of 

 the ventral perisome, which embraces the lowest joints of the pinnules.J The 

 first pinnules of the arms are rather long, with well-marked terminal combs. 

 The length gradually decreases tiU about the loth brachial, and then begins to 

 increase, but there is no specially small pinnide. The terminal comb may 

 continue as far as the 10th brachial, or cease four or five joints sooner-. The 

 pinnule joints may be almost smooth, or they may have strong projections to- 

 wards the dorsal side, even to far out on the arms. 



*• This peculiarity is a very marked one. In no case have I found a syzygy in 

 the first joint of any arm springing from a radial axillary. The ten-armed forms 

 thuij belong to the type of Act. mericlionalis. But individuals with 12, 13, 15, etc. 

 arms are by no means rare, and furnish a complete transition to the large examples 

 with 20 arms to which the specific designation {pulchella) by Pourtalcs is strikingly 

 applicable. 



t This character is esjiecaally distinct in the Ant. alatn. of Pourtales from Bar- 

 bados, and in several siKH-inicns, both ten- and twenty-armed, froni Station 269 (St. 

 Vincent). In other individuals from this station, as in those named Ant. 2>ulchdla 

 (Pourtales), the arms are perfectly smooth throughout their whole length. 



X This is the character which led Pourtales to give the specific name alata to cer- 

 tain individuals dredged by the " Hassler " at Barbados, in which it is especially 

 marked. It occurs also, though less distinctly, in the original specimens of Aitt. 

 pulcliclla. I (iud it to be a very variable one, even among the ditl'ercnt arms of the 

 same individual, some of which arc webbed and others not. 



