362 Dr. 0. Semper on a new Genus o/" Comatulidse. 



The currents by which most parts of the Atlantic are more 

 or less affected, and of which the Gulf-stream is the most im- 

 portant, generally prevail from the west. Along the coast of 

 Norway the action is decidedly from south to north, and has 

 the effect of keeping the entrance of the most northern ports, 

 such as Hammerfest, free from ice at all seasons. To the 

 south of the Bay of Biscay, more particularly south of Gib- 

 raltar, the current sets southward, past the Canary Islands j 

 but I cannot say that I have been able to detect any effect 

 from these currents upon the distribution of Mollusca — a sub- 

 ject to which I have paid some attention. 



It is a remarkable fact that the shells of the Azores are of 

 European and West- African species, and not American, as 

 would have been the case had they been carried there by the 

 prevailing currents ; and, what is still more remarkable, the 

 Littorina most abundant in these islands [L. striata) is not a 

 European species, but common to the Madeira, Canary, and 

 Cape Verde Islands, and to the west coast of Africa — a 

 circumstance deserving the attention of geologists, as pointing 

 to a former distribution of land. 

 Islewortli House, Oct. 16, 1868. 



XLIII. — On Ophiocrinus, a new Genus of Comatulidae. 

 By Dr. C. Semper, of Wiirzburg*. 



Among the numerous Comatulidge found by me at Bohol, 

 there is one species possessing only five, wholly undivided arms. 

 At first I held it to be a young specimen of some real Coma- 

 tula ; but, not corresponding exactly to any of the Philippine 

 species, I consider myself justified in describing it as a separate 

 species. In this case the fact of the arms being undivided 

 gives it a claim to a separate genus. 



Ophiocrinus, n. gen. 



Five wholly undivided arms ; they spring direct from the 

 central knob, which below bears the cirrhi : other ossicula of 

 the calyx are entirely wanting throughout. Disk ? 



Ophiocrinus indivisuSj n. sp. 



Sixteen cirrhi range in a single row around the small flat knob. 

 Joints of the cirrhi 18-20, very knotty, especially at the basis ; 

 the knots correspond to the articulations : the first two joints 

 are short, as high as they are broad ; the third to sixth are 



* Translated by Frau Anna Semper. 



