1887.] NATURAL SCIENCES OF PHILADELPHIA. 205 



and more coarsely spined as they approach the chitinous coats of 

 the statobhists, where they may be reduced to at least -eUo ths. in- 

 ches in length, although often increased to ^o'^o ths. inches in thick- 

 ness, and their spines, which are very irregular in size and situa- 

 tion, often as long as the spicule is broad." Carter. 

 Loc. MacKay's Lake, near Pictou, Nova Scotia. 



(16) Spongilla bohmii, Hilgendorf. Ann. and Mag. N. H. Vol. XII, ISS?,, p. 

 122. 



"Sponge parasitic upon masses of Spongilla nitens, appearing as 

 an inconspicuous crust of only one millimetre in thickness ; consist- 

 ing of a very fine-meshed, delicate frame work. The magnificent 

 gemmulie are grouped in a single layer of from 8 to 12 within the 

 skeleton, but at the same time much projecting from it ; always very 

 few in number. 



"A delicate homogeneous lamella sharply divides the two species. 



"The skeleton spicules are similar in form to those of S. nitens, 

 but are only half their length, and instead of being smooth are stud- 

 ded with roundish, flattened tubercles, Avhich at the ends approach 

 considerably closer together. 



"They are accompanied by a four times smaller amphidiscoid form, 

 whose shaft is gently curved and bears at some distance from the 

 the centre a small spherical elevation. From a similar one at each 

 end of the shaft proceeds five short, pointed, recurved prongs, exact- 

 ly as in a whorl. These double whorls lie close to the large spicules 

 and form with them the netw^ork, the threads, of which are' mostly 

 but one spicule in thickness. 



"The gemmula? have not the layer of parenchyma ; the spicules 

 lie tangentially and in only a single layer ; but they are densely 

 crowded and at the same time minute ; so that their number is very 

 considerable and may exceed a thousand in one gemmule. Each 

 spicule is moderately curved, cylindrical, with only the last eighth 

 or tenth tapering to a point. The surface bears a moderate number 

 of short acute spines ; say 50 on the entire spicule." Slightly ab- 

 breviated from M. Hilgendorf. 



Loc. River Ugalla near Lake Tanganyika, Central Africa ; col- 

 lected by Dr. R. Bohm. 



Through the good offices of my friend Mr. Carter and the kindness 

 of Dr. Weltner, of Berlin, I have been favored to receive from Dr. 

 Hilgendorf of the Berlin Zool. Museum, where it Avas deposited, an 

 excellent specimen of S. nitens, bearing upon one of its surfaces a 



