104 



PROCEEDINGS OF THE ACADEMY OF 



Science and culture ; they are among the reasons why the Academy recog- 

 nizes in his death the loss of a liberal patron, a judicious counsellor and an 

 agreeable associate. 



Resolved, That this expression of the Academy's appreciation of Mr. Wil- 

 stach's worth be communicated to his widow and family, in token of its sym- 

 pathy with their bereavement. 



W. S. W. RuSCHENBERttER, 



Jos. Leidy, 

 (Signed) Wm. S. Yaox. 



S. B. Howell, Rec. Sec. 



The following gentlemen were elected members of the Academy : 

 Green Smith, Thos. Stewardson, H. Weir Workman, W. B. Rogers, 

 Thos. G. Gentry, Wm. H. Pan coast, M. D. 



The following were elected correspondents : Prof. Igino Cocchi, of 

 Florence, Italy ; Prof. John Jas. Stevenson, Ph. D., of Morgantown, 

 W. Va. 



On favorable report of the Committees, the following papers were 

 orderded to be published : 



Notice of some Crustacea of the Genus LIBINIA, with descriptions of four 



new Species. 

 BY T. HALE STREETS. 



Much uncertainty has existed with regard to the identity of certain species 

 belonging to the genus Libinia. Libinia dubia, ever since it was first estab- 

 lished by Milne Edwards, has been regarded as a doubtful species. In the 

 description of it by Edwards, he states that it resembles L. canaliculata very 

 much, and that it is not improbable that it is the young of that species. Nat- 

 uralists in this branch of science down to the present time appear to have 

 accepted this statement as the truth. 



De Kay, in his Natural History of New York, states that the " younger indi- 

 viduals, 1 4 in. in length, are more pyriform in shape, are entirely covered with 

 a dense, downy hair, and the spines are not so prominent as in the adult. In 

 this state I suppose it to be the L. dubia of Edwards." 



Gibbes in an article in the Proceedings of the American Association for 

 1850, regards the two species as distinct, but says that no absolute characters 

 can be indicated by which they may be separated. 



I do not know how to account for this prevailing ignorance, as the charac- 

 ters existing, separating the two species, are so plain. 



Libinia dubia, Edwards. His. Nat. des Crust, vol. 1, p. 300, pi. 14, fig. 2. 



L. dislincta, Guerin. 



Besides the characters usually given as distinguishing this species, the fol- 

 lowing may be observed, and they will be found to be highly characteristic. 



In the median line of the body, couuting backward from the depression sep- 

 arating the gastric and genital regions, there is a row of four spines ; one on 

 the genital region, two on the cardiac and one on the intestinal. One small 

 spine on the posterior part of the gastric region in the median line, and five 

 arranged transversely on the anterior part of the same region. Three prom- 

 inent spines on the branchial region independently of those on the lateral 

 margin. The hepatic region is usually devoid of spines or tubercles ; sometimes 

 there is a very small, sharp one on each side, or, again, it may be present on 

 one side and absent on the other. There is never more than one on a side. 

 The regions are very distinctly marked out. 



Rostrum prominent. Its bifurcated extremity diverging, and directed near- 

 ly horizontally. The cleft deep. 



[Sept. 



