254 PROCEEDINGS OF THE ACADEMY OF [1887. 



fasciculated spicules, that are tliemeelves formed in the deeper parts 

 of the sponge. In T. pen^isylvanica, the spicules are short and 

 slightly, if at all, fasciculated ; and, as the crossing lines are more 

 numerous, they require a greater proportion of these forms of dermal 

 origin. 



(V.) Gen. PAEMULA, Carter. Ann. and Mag. 1881. p. 98. 



Gen. char. Skeleton spicules nearly as in Tubella; generally 

 robust, their ends rounded or abruptly terminated. Dermal spicules 

 sometimes present. Gemmules surrounded by a granular or cellular 

 crust of considerable thickness, charged with or embedding an ar- 

 mature of shield-shaped (parmuliform) si^icules. 



In the species of this genus, all from the River Amazon, South 

 America, or from some of its tributaries, a further modification of 

 the birotulate form of gemmule spicules may be observed. The 

 outer rotule, that, in the last previous genus had become much 

 inferior to the other, has now disappeared, as well as the larger 

 portion of the shaft, leaving only the proximal rotule with an acu- 

 minate umbo, as a "scutulate" or "parmuliform" spicule. 



Our first knowledge of the sponges pertaining to this genus, as 

 well as of three of the Tubellas, already described, is derived from 

 specimens collected by Mr, H. W. Bates during his sojourn upon 

 the Amazon and its branches, from the year 1848 to 1859. His 

 specimens appear to have been generally gathered in the neighbor- 

 hood of Villa Nova, probably in a side channel of the main river; 

 ("Dark Ygapos in virgin forest, margins of Amazons, Villa Nova.") 

 On his return to England they were sent to Dr. Bowerbank, whose 

 descriptions of them form the most interesting and valuable portions 

 of his monograph. 



In the far too meagre narrative that Mr. Bates has given us of 

 his journeyings, ("The Naturalist on the River Amazons," London, 

 John Murray, 1873.) we are informed that the changes of level in 

 this portion of the river between the wet and dry seasons amount 

 to 25 or even 35 feet ; that the floods last from three to four months; 

 and when the water retires "the trunks and lower branches of the 

 trees are coated with dried slime, and disfigured by rounded masses 

 of freshwater sponges, Avhose long horny spiculse and dingy colors 

 give them the appearance of hedge hogs." 



It is rather remarkable that later travellers in this district do 

 not seem to have had their curiosity excited by the singular appear- 

 ance of these encrusting or suspended masses, so far as to induce 



