4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 76 



type by Lambe (stauracts and pentacts, rays 60/j, long) and Schulze 

 (pentacts, rays 80/x, long). 



Hyfodermal pentacts. — Present as prostalia in large numbers over 

 parts of the dermal surface, projecting several millimeters. Some 

 of the surface depressions are, as said, filled with a tangle of these 

 spicules. Parenchymal ray is smooth, slender and tapering, becom- 

 ing very slender toward the free end, reaching 6.5 mm. in length. 

 Paratangential rays about 2.4 mm. long; spines 140/<, long and 

 shorter, on superior-lateral surfaces of ray. Some of the pentacts 

 actually in the substance of the sponge are somewhat smaller than 

 the prostalia and have spineless paratangential rays. The spicules 

 do not differ essentially from those of the type. Lambe gives the 

 proximal (parenchymal) ray as 8 mm. long, paratangential rays 

 about one-third as long. Schulze records that the prostal pentacts 

 include those with (typical) spined paratangential rays and others 

 with these rays smooth; and that the paratangential rays are some- 

 times bent over toward one side (paratropal). 



In the autogastralia the Alaskan sponge differs in a definite detail 

 from the type, even though the specimens assigned to the type would 

 seem to fall in two groups in respect to this point and should there- 

 fore, it would seem, be separated in some fashion in the formal 

 classification. Thus Lambe (1892, p. 73; pi. 6, fig. 2k) records the 

 autogastralia as oxyhexacts, rays roughened and similar, ray length 

 only about Wjx. In Schulze's specimens these spicules are hexacts 

 in which the tangential and parenchymal rays are about 120,a, long 

 and minutely spinose; the free ray longer than the others, up to 

 SOOyu, long, and more strongly spinose. Schulze (1897, p. 36) does 

 not speak of this difference between his record and that of Lambe 

 and the difference may conceivably be due to Lambe's having ex- 

 amined a specimen in which the actual autogastralia had been largely 

 washed away. 



In the autogastralia of the Alaskan sponge (fig. 2) the four tan- 

 gential rays are strong, minutely and sharply spinose, tapering to 

 points, characteristically about 350/^ long and 40/x thick at the base. 

 The length of these raj^s, measuring from center of spicule, ranges 

 in general from 315/a to 385/x. One of the four is occasionally 

 shorter (250;a) than the others and smooth. Smaller spicules (pre- 

 sumably younger forms) also occur very sparingly; in these the six 

 are about all alike, the ray length in the actual measurements rang- 

 ing from ^lOjx to 140;a. The tangential rays of the autogastralia in 

 general are arranged regularly as to make squarish meshes, the side 

 of the mesh approximately equalling in length a spicule ray. The 

 parenchymal ray is usually but not always shorter than the tangential 

 rays of the same spicule, the range in actual measurement being 

 250ju, to 380;^ ; tapering, pointed, smooth, or feebly spinose. Free ray 



