REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 149 



work, penetrating the dermal membrane in a great number of places 

 to form spiny elevations. Consistency rigid but brittle. 



Megascleres short, stout, and cylindrical amphioxea with abruptly 

 pointed tips, occasionally true amphistrongyla, smooth to feebly 

 microspined; length range 115-175 /x, width range 14-25 n. A smaller 

 type of megascleres occasionally present; these are strongly spined, 

 bluntly pointed amphioxea, of an average length of 95 n. 



Microscleres feebly curved, fusiform, and sharply pointed amphi- 

 oxea, covered with small granules at their tips and bearing large and 

 erect spines in then* central portion; length range 65-75 /x, width 

 range 2-3 m. 



Gemmoscleres tubelliform, lower rotule almost invariably circular 

 with an entire, slightly recurved margin; shaft ranging from smooth to 

 bearing a few spines; terminal knob bearing a small number of minute 

 recurved teeth; length range 20-37 /x, diameter of rotule 18-21 n, 

 of knob 7 ju, width of shaft 2-4 /x- 



Gemmules subspherical, ranging in diameter 400-650 n; pneumatic 

 coat feebly developed, almost granular; gemmoscleres embedded in 

 a manner typical for the genus; foramen produced into a very short 

 porus tube. 



Distribution. — Known only from the type locality in the Ama- 

 zon R. 



Color in life. — Not yet recorded. 



Discussion. — While the presence or absence of free microscleres 

 was not mentioned in the original descriptions of this species. Gee 

 (1933c) failed to recognize them in the type material reexamined by 

 him. Such microscleres, however, are present in the type, although 

 they seem to be very rare. 



The only gemmule examined during the present studies is much too 

 mutilated to allow reliable comparisons with those of other species of 

 this genus. The pneumatic layer appears granular, whereas in the 

 majority of other species it is composed of rather large air spaces. 

 It is hoped that M. reticulata can soon be relocated in South American 

 waters so that additional taxonomic evidence can be demonstrated. 



Metania vesparia (von Martens, 1868) 



Plate 14, figures 5-12 



Spongilla vesparium von Martens, 1868, p. 61. 



Tubella vesparium Weltner, 1895, p. 114. — Annandale, 1911c, p. 54; 1918a, p. 213. — 



Gee, 1929d, p. 297; 1930a, p. 105; 1933c, p. 248.— Penney, 1960, p. 59. 

 Tubella pottsi Weltner, 1895, p. 143; 1913, p. 475.— Annandale, 1914, p. 245.— 



Gee, 1931e, p. 46; 1933c, p. 240.— De Laubenfels, 1936, p. 37.— Penney, 



1960, p. 59. 

 Acalle pottsi Burton, 1934, p. 412.— Arndt, 1936, p. 17. 

 Metania lissostrongyla Burton, 1938, p. 463. — Penney, 1960, p. 45. 



