300 DR. J. 6. BOWERBANK ON THE SPONGIAD.E. [May 5, 



spicula afford the most prominent specific characters of the species. 

 The normal form is that of a regular attenuato-expando-temate 

 connecting spiculum, the three radii of which are as nearly as possible 

 equal ; but they are very rarely found in this state. Sometimes one 

 or two of the terminal radii are absent or only partially developed, or 

 one or more of them terminate hemispherically. If the radii are 

 completely produced, their apices are mostly recurved or they 

 assume various contortions. If I had had the type specimen only 

 for examination, I might have imagiued that these malformations 

 and contortions of the radii were those of the individual only ; but I 

 carefully examined microscopically the other three specimens to see 

 whether their spicula agreed in the imperfect development of the 

 radii of the ternate connecting ones of the type specimen ; and I 

 found in all of them the same contorted or undeveloped condition 

 of their radii that forms so striking a character in the type one. 



The interstitial membranes are abundantly furnished with the two 

 forms of stellate retentive spicula, which, from their structural pecu- 

 liarities, afford very efficient specific characters. The sphero-stellate 

 ones with cylindro-subfoliate radii are rather the more numerous of 

 the two forms : they do not differ to any great extent in their 

 diameter ; a perfectly developed one measured extreme diameter 

 y-gipg- inch. The attenuato-stellate ones vary considerably in their 

 amount of development ; many of them have comparatively a small 

 number of radii, and in such cases they are frequently subsphero- 

 stellate : but this does not appear in the fully developed forms, where 

 the radii are too numerous to be counted ; a large one of this descrip- 

 tion measured extreme diameter y^Tuf mcn - 



The ovaria are more or less oval and are depressed to a consider- 

 able extent ; their length is frequently nearly twice thr.t of their 

 diameter. They are abundantly dispersed on the surfaces of the in- 

 terstitial membranes, and may be seen in every stage of development, 

 from a minute multistellate form to that of the adult ovarium. 



Gteodia reticulata, Bowerbank. (Plate XLVI. figs. 14-20.) 



Sponge massive, sessile. Surface smooth, minutely reticulated. 

 Oscula small, congregated irregularly. Pores inconspicuous, evenly 

 dispersed. Dermal membrane unknown. Skeleton — fasciculi com- 

 pact, abundantly spiculous ; spicula fusiformi-acerate, rather slender ; 

 connecting spicula attenuato-patento-ternate, stout and long, numer- 

 ous, radii moderately long ; and recurvo-ternate long and rather 

 slender, numerous ; also, rarely, porrecto-teruate long and slender. 

 Interstitial membranes — tension-spicula fusiformi-acerate small and 

 slender, often flexuous ; retentive spicula attenuato-stellate very 

 numerous, radii few ; also cylindro-stellate, exceedingly abundant 

 and very minute, radii rather numerous. Ovaria small, spherical, 

 rather numerous. 



Colour in the dried state cream-white. 



Hub. Mexico (Mr. Thos. Ingall). 



Examined in the dried state. 



I received this sponge from my late friend Mr. Thos. Ingall, 



