EEPORT ON THE HEXACTINELLIDA. 269 



tinellicla collected on the coasts of Spain and Portugal, a full-grown siliceous skeleton 

 which he identified as Farrea occa, Bowerbauk. 



This form consists of a continuous branched tube exhibiting anastomoses here and 

 there, and measuring from 5 to 8 mm. in diameter. The tube opens by a slightly funnel- 

 shaped, expanded and projecting cup about 1 cm. in width. To conclude from the figures 

 given * all the tubes consist only of a simple framework with quadrate meshes. Although 

 in this the specimen described by Saville Kent quite agrees with the network of siliceous 

 beams, regarded by Bowerbank as the dermal skeleton of his Farrea occa, yet it difi"ers 

 from the latter in the circumstance that the beams of the framework are not smooth 

 externally, but are beset with pointed tubercles. In this character it rather resembles 

 the siliceous network regarded by Bowerbank as part of the inner body skeleton of his 

 Farrea occa. 



On the same Lophohelia stock upon which the specimen which was determined as 

 Farrea occa, Bowerbank, had been found, Saville Kent also observed some " small 

 fistulose ramifications bridging over the minor interspaces between the branches of the 

 coral." He regarded this sponge, in spite of the great similarity with the adjoining Farrea, 

 as a species belonging to another, and even a new genus, which he named Aulodictyon. 

 From the genus Farrea this is said to difi'er in the following points : — " In Farrea 

 the basal skeleton is composed of a single reticulated lamina ; in Aulodictyon the 

 basal skeleton consists of a complex reticulate tube between, and continuous with 

 the primary meshes, of which an abundant network of coalescing simple hexradiate 

 stellate spicula occurs." Moreover " the minuter spicula of the sarcode" are also said to 

 be " of an entirely different type." And since Oscar Schmidt had, in the case of his 

 Farrea facunda, described no single-layered dictyonal framework in the basal part, but a 

 complicated network of several layers, and isolated spicules, similar to those found by 

 Kent in his Aulodictyon, the latter was of opinion that Schmidt's Farrea facunda ought 

 to be referred as Aulodictyon facundum to his new genus. 



As I shall show further on, however, all tubular species of Farrea have in their 

 basal portion a dense dictyonal framework of several layers, and also the " long attenuate 

 spicules inflated at the extremity and reflecto-peltate, with a dentate margin or with 

 a simple series of recurved hooks," which Kent looks upon as characteristic peculiarities 

 of his genus Aulodictyon. Consequently the genus Aulodictyon must be entu-ely 

 abandoned. 



In the survey of all the above described HexactineUida which Carter gave in 1873,^ 

 this accurate observer first sharply distinguishes the two sdiceous networks found on the 

 already often mentioned original specimen oi Fiq)lectella cucumer, Owen. These had been 

 described by Bowerbank as dermal and body skeleton of one and the same sponge, while 



1 Loc. cit., pi. Ixiv. fi-s. 12, 13, 14. 



^ Aim. and Mag. Nat. Hist, ser. 4, voL xii. p. 3G0. 



