Miscellaneous. 390 



mesenterioid laminae. The sclerobasc is very delicate, and its surface 

 is marked with striae like those of red coral. 



An Isidine coral is described under the name of Melitcea oranensis. 

 The remains are rootlets and calcareous joints, of various form, but 

 presenting the form and structure of those of Melitrea. The rami- 

 tication was dichotomous. 



A. fragment of a sclerobasic axis of stony texture and formed of 

 concentric layers is referred by the author to the genus GorgoneUa, 

 under the name of G.? anomula. 



Of the Pennatulidac the author notices the following forms : — Vir- 

 f/iiJaria saheliensis had a long, cylindrical, straight, and smooth style, 

 showing a radiated structure ; Graphidaria barhara had a style 

 differing from the type of the genus in wanting the longitudinal 

 furrow; C'celor/nq^hula subconipressa is the type of a new genus having 

 a fistulous style. The style is elongated, straight, nearlj" smooth, 

 slightly compressed, convex on one surface, a little depressed at the 

 edges of the opposite side, the middle of which has an obsolete 

 ridge. 



These species, except the last, are found in the vicinity of Oran, in 

 beds named Sahelian by the author and synchronous with the Tor- 

 tonian beds of the Italian geologists. Ccelor/rcqjJiula suhcompressa 

 occurs in the Cartennian of Milianah, immediately below the Hel- 

 vetian with Ostrea crassissma, — Comjjtes Rendus, November 9, 1868, 

 p. 963. 



Are Unios sensitive to Light '7 By C. A. White. 



Those who have studied the habits of Unios in their native ele- 

 ment are of course well aware of their habit of bur5-ing themselves 

 in the mud or sand, leaving only the posterior portion projecting, 

 for the purpose of giving ingress and exit to the respiratory cur- 

 rents of water. The sensitiveness of the margins of the incurrent 

 and excurrent orifices to the slightest touch is also well known ; 

 but during the past summer, while collecting moUusks in one of the 

 rivers of Central Iowa, I became comanced that these, or adjacent 

 parts, were also keenly sensitive to light. 



Unios were found numerously occupying the position referred to, 

 plying their currents industriously through their distended orifices ; 

 but whenever my shadow in the bright sunlight came suddenly 

 upon them, they invariably closed their orifices quickly and com- 

 pletely. This was repeated a great many times, and upon the same 

 individuals, to assure myself that it was not caused by any agitation 

 of the water or movement of impurities in it that might produce 

 irritation of the parts. It was evidently the interception of the 

 sun's rays alone that caused them so suddenly to close their orifices ; 

 yet it is worthy of remark that they did not quickly close them 

 if sunlight was suddenly admitted to them while respiring in the 

 shade. 



The question then ai'ose in my mind as to the possibility that the 

 parts were sensitive alone to the rays of heat from the sun and not 



