230 PROCEEDINGS OF THE ACADEMY OP [1886. 



the distinctive line comparatively unimportant. Heretofore, 

 between tlie genus Spovgilla and those genera comprising the 

 other group, there has been " a great gulf fixed." One only case 

 in the past has suggested their possible association, or the 

 development of one group from the other. 



In Meyenia acuminata, Potts (Proc. Acad. Nat. Sci. Phila., 

 1882, p. 69), since regarded as a variety of M. Jluviatilis, the 

 shafts of the birotulates are prolonged at each extremity, form- 

 ing acuminate terminations some distance beyond the surface of 

 the rotules. In position, also, these spicules are abnormal, lying 

 flat upon the chitinous coat, instead of resting upon one rotule, 

 their shafts taking the position of radii, as is usual in this form. 

 In fact we have the spicules of a Meyenia occupying the ordinary 

 positions, and in degree approximating the forms of those pecu- 

 liar to the SpongilliB. 



In the present instance their intermediate character is still 

 more striking, and while their form and position probably more 

 closely associate them with the genus Spongilla in which the 

 species has now been placed, the grouping of the ray-like species 

 clearly suggests Meyenia. It has been an altogether unprece- 

 dented experience with the author to hesitate between these two 

 genera, and it will be no cause of surprise if the future teacher 

 shall shift it from its present position. 



It must not escape notice that in both of these instances the 

 gemmuliB are without " crust;" that it is difficult to understand 

 how birotulates could be supported in their ordinary i)ositions 

 without these embedding granules ; and that we may not unrea- 

 sonably infer that the change in position has induced the modifi- 

 cation of type that we here find. 



This collection of sponges, including the new species, has been 

 examined coincideutly by H, J. Carter, Esq., F. R. S., and their 

 identification and this description are believed to meet his 

 approval. 



April 1.3. 



Mr. John H. Redfield in the chair. 



Nineteen persons present. 



The death of the Hon. John Welsh, a member, was announced. 



April 20. 



Mr. Geo. W. Tryon, Jr., in the chair. 



Fifteen persons present. 



The death of Andrew Nebinger,M.D., a member, was announced. 



