94 U.S. NATIONAL MUSEUM BULLETIN 2 72 



dermal membrane well developed. Skeleton consisting of polyspicular 

 vertical and much slimmer and irregular horizontal fibers, joined 

 together by a small amount of spongin. Consistency of live sponge 

 moderately hard and firm, skeleton of dry sponge very coherent. 



Megascleres feebly curved to straight, stout, and distinctly fusi- 

 form amphioxea, thickly coA^ered with small spines except at their 

 tips; length range 290-370 n, Avidth range 15-28 /x. 



Microscleres absent. 



Gemmoscleres typically birotulates of one class, but of distinctly 

 varying length ; their shafts are very stout and cylindrical, invariably 

 armed with at least 2-3, and up to 12-16 rather large spines that are 

 often subdivided or otherwise malformed; their rotules are of more 

 or less equal diameter, of irregular outline in lateral view, irregularly 

 incised in a number of lobes and rays, their outer surface often dis- 

 tinctly granulated; length of shaft 38-65 /x, occasionally even longer, 

 diameter of rotules 23-28 Mj width of shaft 6-8 n. 



Gemmules moderately abundant in mature sponge, spherical, 

 ranging in diameter 410-500 fi; pneumatic coat well developed and 

 distinctly granular, consisting of minute spherical air spaces; gem- 

 moscleres embedded in this coat in a single layer, their distal rotules 

 as a rule not protruding thi-ough the well-defined outer gemmular 

 membrane, which has a ripply appearance; foramen distinctly ele- 

 vated, in height almost reaching to level of outer gemmular membrane, 

 never tubular. 



Distribution. — Known from various areas in the Indo-West 

 Pacific region, ranging from Indonesia to the Philippines, Japan, 

 and the New Hebrides. 



Color in life. — Yellowish brown (straw color). 



Discussion. — Gee (1930a) tabulated the differences between E. 

 Jortis and its two "varieties" E. f. hebridensis and E. f. vorstmani and 

 compared all three sponges \\dth other closely related species of the 

 E. ramsayi group. Although Gee found that the two varieties closely 

 resemble E. fortis, he considered them sufficiently distinct to be 

 separated at a subspecific level. The reexamination of all these spongil- 

 lids demonstrated beyond doubt that their racial distinction cannot 

 be contemplated, since the various criteria are by no means constant 

 in the same specimen. It is obvious that E. jortis displays certain 

 features that can be interpreted as ecomorphic malformations in a 

 particular habitat, such as is also perceptible in any range of E. 

 ramsayi. The "variety" E. j. hebridensis represents an extreme of 

 such an abnormal development, while most of the scleres of E. /. 

 vorstmani seem outright "freaks." 



Considering all criteria, the entire E. fortis group seems to differ 

 from E. ramsayi merely by its possession of much stouter spicular 



