^°l89x''] PROCEEDINGS OF THE NATIONAL MUSEUM. 361 



* * * " 111 tli«* (lie(lgiiijj;s of tli(i /iZaAre ill tlie Gull" of Mexico, off the 

 West Indies, and in the Caribbean, ray attention liad aheady been 

 call<'d to the immense amount of vegetable mntter dredged n[) from a 

 depth of over 1,500 fathoms on the le(i side of the West india Islands. 

 lint in none of the dredgings on the Atlantic side of the isthmus did 

 w<i come nj)on such masses of decomposed vegetable matter as Ave 

 found on this expedition. There was hardly a haul taken which did 

 not sujjply a large cjuantity of water-logged wood, and more or less fresh 

 twigs, leaves, seeds, and fruits, in all possible stages of decomposi- 

 tions." * * * 



WEST AMERICAN CURRENTS. 



Again referring to Agassiz, he says : " The course of the currents along 

 the Mexican and the Central and South American coasts clearly indi- 

 cates to us the sources from which the fauna and flora of the volcanic; 

 group of the Galapagos has derived its origin. The distance from the 

 coast of Pjcuador (Galera Point and Cape iSan Francisco) is in a direct 

 line not much over 500 miles, and that from the Costa Kica coast but 

 a little over 000 miles, and the bottom must be for its Avhole distance 

 strewn thickly with vegetable matter, Avhich, as I have already stated, 

 came up in great masses in almost every haul of the trawl. This was 

 especially noteworthy in the line from the mainland to Cocos Island, 

 and certainly off<'is a very practical ob)e(;t lesson regarding the manner 

 in which that island must have receised its vegetable products. It is 

 only about 27.5 miles from the mainland, and its flora, so similar to that 

 of the adjacent coast, tells its own story." " The velocity of the currents 

 in the Pauamic district is very great, sometimes as much as 75 miles a 

 day, so that reeds, fruits, masses of vegetation harboring small reptiles, 

 or even large ones, as well as other terrestrial animals, need not be 

 atloat long before they might safely be landed on the shores of the 

 Galapagos. Its flora, as is well known, is eminently American, while 

 its fauna at every jmiiit discloses its affinity to the Mexican, Central, or 

 South American, and even West Indian, types, from which it has prob- 

 ably originated; the last indicating, as well as so many of the marine 

 types collected during the expedition, the close connection that once 

 existed between the Panamic region and the Caribbean and Gulf of 

 Mexico; a connection once extending, probably, through deep and 

 wide passages all the way from the northern extremity of Colombia, 

 the Isthmus of Panama, Costa Eica, and as far north as the Isthmus of 

 Tehuantepec." 



TERRESTRIAL MOLLUSKS. 



The land shells are principally of a Bulimoid type and of a dis. 

 tiuctly American aspect. One of the twenty or more so-called species, 

 Bulinms aehatinellinus of Forbes, has in the brightness of its coloration, 



