[6-l-J MR. JAMES RITCHIE ON UVDROIDS [May 28, 



leaves, which are altogethei- fiee from one auothei'. Every leaf 

 bears a row of 6 or 7 large bulging nematophores on each margin. 

 The cosnosarc from which the portions supplying these nemato- 

 phores branch oif runs up one side of the leaf, sending oS' as it 

 passes a short pi-ocess into each nematophore on that side, and 

 then, having passed a considerable distance up the leaf, sends off a 

 larger shoot which, running backwards, supplies the nematophores 

 along the other side. Conforming with thLs branching of the 

 cwnosarc, the creuosarc-containing cavity iu the leaf also .shows a 

 backward-running bi-anch connecteil with the nematojihore-cavities 

 along one side {vide PI. XXIV. fig. 10). Witliout the walls of 

 this cavity there is a delicate chitinous membrane connecting 

 the nematophores and forming a wing-like extension to the liody 

 of the leaf proper. The .specific name maryinata indicates the 

 presence of this extension. At the base of each leaf along only 

 one side of the corbula there is a very small spur-like nematophore. 

 Locality/. Growing on the bottom of lighters ; St. Vincent, 

 Cape Verde Islands ; 20th and 30th July, 1904. 



LvTOCARrrs graxdis, var. unilatekalis, var. n. (Plate XXV. 

 figs. 1, 2, 3.) 



Many much-bi'anched colonies have been obta,ined from one 

 locality : the largest, which is fi'agmentaiy, is 20 cm. in height, 

 with a .stem 6 mm. in diameter above the first branch, and a large 

 basal poi'tion covered with loose hydrorhizal tubes. 



The stem is .strongly fascicled and is divided near the base into 

 several large branches, which bear smaller branches and so on 

 sometimes to the sixth ordei'. All the bi-anches, except the 

 smallest, spring from their parent branch on the side remote from 

 the stem, a rather unusual arrangement to which the variety 

 owes its name. The hy(h'oclade-bearing tubes are divided into 

 i-egular internodes, 0'4 to 0'5 mm. in length, each of which bears 

 an alternate hydroclade almost on its anterior surface. 



The hydroclades, which ai-e borne on a perforated proce.ss of the 

 internode, are about 8 mm. long, and are divided into internodes 

 0'35 mm. in length, each with two very strong septal ridges, one 

 opposite the intrathecal ridge and horizontal, the other less distinct 

 opposite the base of the lateral nematophores and sloping obliquely 

 upwards. 



The hydrothec-e are closely approximated, deep, slightly bulging 

 below, with nine teeth, seven of which are apparent wliile one on 

 each side is hidden by the latei'al nematophore. The anterior 

 tooth is slightly recurved. The intrathecal riilge is distinct and 

 is horizontal, extending around the h\'drotheca about 1- from the 

 base. The mesial nematophores are long, adnate almost to the 

 top of the hydrotheca and then free for some distance. The free 

 portion varies much in length, sometimes scarcely rising above 

 the hydrotheca on the proximal end of a hydroclade while over- 

 topping those on the distal portion for a considerable distance 

 (e/. PI. XXV. figs. 2 it 3). In the supra;alvcine nematophores 

 510 



