76 



Dr. G. J. Pliiule on the Genus liiiidia. 



sponge, in which the real union of the spicules cannot be dis- 

 tinguished. 



Having obtained some of the spicules of Hindia in a silici- 

 fied condition and isolated from each other and from the 



Fig. 1. 



Fig. 2. 



Fig. 1. — ff, a fragment of the skeleton of Hindia Jihrosa, Roem., sp., 

 showing in places the junction of the spicular rajs; drawn from a 

 longitudinal section of a specimen from New Brunswick. 4, the 

 fourth or truncated ray of the spicides. h, c, two isolated siliceous 

 spicules, viewed laterally, d, another spicule seen from below, 

 showing the central node and the expanded ends of the rays, e, 

 another spicule seen from above, showing the end of the fourth ray. 

 Drawn under the camera lucida to the scale of 70 diameters. 



Fig. 2. — Portion of a tangential section of Hindia Jihrosa, showing the 

 apertures of the radial canals. The individual spicules cannot be 

 distinguished. Drawn to the same scale as fig. 1. 



matrix, I am enabled to give further particulars respecting 

 their form than could be obtained from studying them in the 

 microscopic sections. In all the detached examples, which 

 might be deemed complete, four arms or rays are present, 



