228 DR. J. MURIE ON STEERE'S SPONGE, 



Towards the fixed end (or centre) the arms are thickest, and throughout are minutely 

 tuberculate or subspined ; the arm extremities are smoothish and pointed. It is by the 

 overlapping of the horizontal arms (fig. 23, a), and this to a considerable extent, that the 

 squares are produced, whilst the horizontal arms respectively project outwards and inwards. 

 The outermost tip frequently bears the small rosette (fig. 23, b) already described. 



Besides the foregoing spicula (save the large rosette), all present in abundance, I met 

 with, by chance, at least in one of the slides of objects examined, another form of minute 

 but not measured spiculum (fig. 27). Whether this had accidentally got amongst the 

 debris shaken out of the Dendrospongia, or otherwise forms a constant part of the latter's 

 skeleton, I cannot say positively. Possibly this spiculum in question forms but a seg- 

 ment of a " rosette with short arms and long, straight, pointed rays," similar to what Carter 

 figures from Euplectella aspergillum (Ann. & Mag. Nat. Hist. ser. 4, vol. xii. pi. xiii. fig. 3) ; 

 only one or two examples were observed by me. I have figured it rather to arrest future 

 attention than to insist on its being an integral part of the sponge under consideration. 



Remakes on the eoregoing. — Prom what precedes it will readily be admitted that 

 Steere's sponge is one among the many already singular forms of the Vitreous Sponges 

 of considerable interest. In size, shape, and structural detail it differs sufficiently from 

 others of the known Hexactinellida, as I presume, to warrant generic and specific dis- 

 tinction, while it no less combines certain peculiarities assimilative and explanatory, to 

 some extent, of moot points in the construction and history of this altogether remarkable 

 group. Its dendroid or shrub-like branching aspect has suggested the generic appellation 

 I submit ; and the collector's name, to whom I am so much indebted, I convert into its 

 specific title. Its habitat but adds another to the many strange and delicate marine 

 organisms hitherto obtained in the Philippine seas ; and doubtless when hereafter studied 

 in its live conditions some curious traits in its history may be unfolded. 



Dendkospongia Steerii, gen. et sp. nov. 



Hexactinellid sponge characterized by its dendritic or shrubby contour ; occasionally 

 attaining a height of 3 feet or possibly more. Branches forking or dichotomous, with 

 continuous whorled series of spicular tufts from base to apices. Skeleton only known ; 

 basework composed of relatively stoutish glassy fibres of coalesced, sexradiate and spino- 

 mucronate spicula, disposed in tolerably compact trabeculae. Main direction of fibre 

 longitudinal to axis, in parallel straightish or slightly bent lines where continued into 

 exterior whorls ; intercrossing fibres more irregular, as are the very numerous excretory 

 canals. Oscula and pores of moderate size distributed all over the free surfaces. Plesh- 

 spicula abundant, and of scopuline, acerate, and rosette shapes. A dermal veil of 

 slender, interwoven hexactinellid spicula probably clothes the major portion or possibly 

 the entire sponge. 



Sab. Philippines, Channel between Negros and Zebu, from 70 to 100 fathoms ? 



In discussing and assigning the affinities of this choice, indeed elegant, sponge, one 

 naturally first looks to the kindred stock from the Eastern Archipelago. To the Miplec- 

 tella group, including the genus Mabrodictyon (Corbitella and Heterotella, Gray), their 



