204 



GEODIA MEDIA. 



2.5-3 n broad and 4-5 long, the longer diameter being situated radially to the 

 umbilicus. These periumbilical rays bear from seven to ten lateral and usually 

 also some terminal spines. In Bowerbank's type the sterrasters measure 100- 

 110 by 82-94 l)y 70-74 p.. Sollas gives their dimensions as 110 by 80 ix. 



Abnormal sterrasters, sterroids, with fewer and more distant protruding rays 

 are met with quite frequently. In these spicules (Plate 16, figs. 20, 21) the 

 parts of the surface destitute of rays bear spines similar to those forming the 

 verticils on the rays of the normal sterrasters. Some of these spines are 

 scattered singly, others arranged in rosette-like groups. The protruding rays 

 of the sterroids attain a thickness of 12-15 /x and a length of 10-12 /x. Their 

 sides are quite smooth ; the rounded end is densely spined. 



All the eight specimens of this species were collected on October 26, 1904, in 

 the Gulf of Panama, off Panama, on the shore of the islands of the Station 

 Pacific Mail Steamship Company or of the Taboga Islands. Bowerbank states 

 that his specimen came from "Mexico." Thinking that the Gulf of Mexico 

 must be meant, when the locality of a marine organism was given as Mexico, 

 in 1903 I gave the Gulf as its locality. Now that this species has been found 

 in the Gulf of Panama, it seems much more probable that Bowerbank's type 

 came from the Pacific coast of Mexico and not from the Gulf of that name. 



Whichever of the two kinds of dermal apertures are the afferents and which 

 the efferents, there can be no doubt, that both are cribriporal. For this reason 

 I now place these sponges in Geodia and not in Sidonops as, following SoUas's 

 suggestion, I formerly (1903) did. 



