ini'i.uii.s — HK'i(u;s. ;3l 



The t'i)k>iiy, 16 cm. in heiglit, consists oi a maiu stem, 3 mm, in 

 (liann'ttM-, Avliicli is destitute of liydrucladia. The basal portion of the 

 stem is missing. At a lieiglit of 5-5 cm. branching begins, (lie largest 

 primary branch having a diameter at the base oi 'A mm., ami a length of 

 12 cm. The secondarj- branches, up to S cm. in leugth, are abundant 

 and irregularly arranged, varying in position fi'om alternate, through 

 sub-alteniate to oi)posite. A few small branches of the third order also 

 occur. The stem, branches, and branchlets are all strongly fascicled. 

 In transverse section the stem is seen to be made up of a great number of 

 tubes — as many as fifty-seven being counted. The polysiphonic branches 

 and branchlets consist of a hydrocladiate tube, supported by a varying 

 number of accessory tubes. The hydrocladiate tube runs along the 

 surface of the branches, but in the stem it looses its superficial position, 

 and, becoming immersed in the accessory tubes, occupies a central or 

 axial position. The hydrocladiate tube is iilone divided into internodes, 

 which are separated by distinct nodes. About the middle of each 

 internode is a process upon which a hydrocladium is set. The hydro- 

 cladia arise alternately from the hydrocladiate tube, and reach a length 

 of 8 mm. Each hydrocladium commences with a long proximal 

 interi^ode sepai'ated from the tube process by a transverse node, and from 

 the next succeeding hydroclade internode, by an articulation, very oblique 

 in lateral Anew, and x-esembling from the front two cones, the points of 

 which interpenetrate. The remaining internodes are considerably shorter 

 than the proximal one, and are separated by slightly oblique nodes. 



The gonangia are boi-ne singly on the branches at the bases of the 

 hydrocladia, and not on the phylactogonia as in A. verrllli, Nutting. 



In his introductory I'emarks on the structures for the protection of 

 the gonangia and their contents among the Plumularida;, Nutting'' states 

 that " in AiilcuiphenojiJb-is the phylactogonium is supposed to be a greatly 

 reduced mesial nematophore of the proximal hydrotheca," In A. vaga 

 the phylactogonium does not occupy the place of a mesial sarcotheca, but 

 springs from one side of the proximal internode of the hydrocladium, 

 originating from that part of the internode, which is between the node 

 and the base of the hydrotheca. The phylactogonium apparently 

 intrudes between the mesial sarcotheca and the base of the hydrotheca, 

 since the sarcotheca is there, but, as it were, forced out of its natural 

 position. It is true that this sarcotheca does not I'epresent the ordinaiy 

 type of mesial sarcotheca ; it is not in contact with the hydrotheca, and 

 is much wider and similar in size and shape to the cauline sarcothecse on 

 the hydrocladiate tube. It is doubtful whether the phylactogonium is a 

 modified mesial sarcotheca, either in my specimen or in the American 

 species, and Nutting also seems dubious, as is evident from his i-emark 

 " it is impracticable to insist in all cases on such homologies." 



The pliA-lactogonium is a jointed, unbranched appendage, bearing a 

 single row of sarcothectc, and one or two terminal hydrothecse. Accord- 

 ing to Nutting, this type of protective appendage is "unique among the 

 Statoplea, and if consistent would prove an excellent generic character.*' 

 In .1. vaya either one or two terminal hydi'othecae are present. Both 



Nuttiug— American Hydiuids, pt. 1., — i'himularida!, I'JUO, p. 35. 



