54 



Ithabdocalyptus dawsoni (Lambe). 



1892 L. M. Lambe in Transact. R. S. Canada, Sect. IV, 1892, p. 73. 



(Taf. XI, Fig. 6—14.) 



Unter der Bezeichnung Batliydonts dawsoni hat Lawrence M. Lambe zu Ottawa (Canada) 

 in den Transactions of the Royal Society of Canada, Sect. IV, 1092, p. 73 eine neue Hexactinellide 

 folgendermaßen beschrieben : 



„Sponge (PI. lY, Fig. 2) nearly or quite erect, straight or slightly curved, subcylindrical, about 

 275 mm in height, with a small base, where it has a diameter of 20 mm. At midheight the maximum 

 diameter is 50 mm whence it gradually decreases in breadth until it has a diameter of 35 mm at its 

 Upper extremity. The wall has an average thickness of 7 mm becoming thinner near the oscular 

 margin which is provided with a fringe of long smooth, diact marginalia with pointed ends and having 

 an average length of 50 mm. The surface exhibits regularly distributed openings with an average 

 diameter of 0,5 mm and is rendered villose by the presence of long, sharp - pointed, smooth pleuralia 

 which have a maximum length of about 60 mm. The gastral surface is smooth and has openings 

 similar to those seen in the dorsal. Texture soft. Colour in spirit light yellowish-grey. 



Skeleton (PI. VI, Fig. 2). Composed of a loose lattice-like reticulation of long, smooth diacts, 

 which lie subparallel to the surface. 



Spicules. The parenchymalia consist of: a) principalia long, slender, smooth, sharp pointed 

 diacts (oxea) with a maximum size of 11,06 mm by 0,1 mm (PI. VI, Fig. 2'); b) comitalia, long, 

 slender, smooth diacts, which have rough inflated and generally bluntly pointed but sometimes round, 

 club-shaped ends (PI. VI, Fig. 2 a, 2 a', 2 b, 2 b'), maximum size 8,8 by 0,01 mm. These comitalia 

 frequently develop two or four rounded tubercles or elevations at the centre. Besides these there are 

 the foUowing: c) intermedia, i) numerous oxyhexasters (PI. VI, Fig. 2 c), having an average diameter 

 of 0,06 mm with long, bent, smooth terminal rays, 2) numerous oxyhexacts, with straight smooth, 

 pointed rays (PI. VI, Fig. 2 d) ; average diameter 0,085 ^he subdivision of one or more rays 



of the oxyhexacts, forms like the oxyhexasters are evidently developed, as modifications between 

 these extreme forms are numerous. 3) Small discohexasters (PL VI, Fig. 2 e) with strong principal 

 rays bearing about six short, slightly divergent, straight terminals. Hypodermal pentacts (PL VI, 

 Fig. 2 f, 2 g) with a smooth proximal ray about 8 mm in length, occur in the dermal skeleton. The 

 four tangential rays are spined, generally curved slightly inward and are about one third the length 

 of the proximal ray. The dermal membrane includes a large number of small rough pentacts and 

 tetracts (PL VI, Fig. 2 h, 2 i) w^hose rays are about 0,06 mm in length. The gastral skeleton is devoid 

 of hypogastralia and consists of numerous rough oxyhexacts (PL VI, Fig. 2 k) with rays averaging 

 0,06 mm in length. 



The writer has much pleasure in associating with this sponge the name of GEORGE M. Dawson 

 to whom Science is indebted for so much new Information relative to the marine invertebrate fauna 

 of the Pacific coast of the Dominion. 



Locality. OfF the mouth of Qualicum River, Vancouver Island, in forty fathoms, sand and 

 gravel one specimen (figured). Strait of Georgia near Comox, Vancouver Island, in forty fathoms, two 

 specimens about 90 mm in length wiht some fragments." 



