172 CARNEGIE INSTITUTION OF WASHINGTON. 



to whom we owe our introduction to Mr. Cipriani, as well as to Judge 

 Blackwood Wright and others whose interest and kindness leave upon 

 all of us a charmed impression of this most beautiful tropical island, a 

 region wherein one may enjoy all the advantages of highly inteUigent 

 civilization and yet be surrounded by the most luxuriant and varied 

 forest of the New World. 



Being situated about 20 miles north of Trinidad, Tobago is separated 

 from the muddy shore-waters which creep westward along the South 

 American coast. The island, surrounded by pure blue ocean-water, Ues 

 directly in the course of the northern branch of the Great Equatorial 

 Current of the Atlantic, which drifts upon this region from the distant 

 coast of Africa. Thus the pelagic life of the tropical Atlantic is carried 

 dii-ectly upon the shores of Tobago, and the island affords an unrivaled 

 situation from which to study the floating animals of the warmest 

 parts of the ocean, thus enabling the Director to make a notable addi- 

 tion to his observations and drawings of the siphonophores. 



The greater part of the land area of Tobago is of igneous and plutonic 

 rocks, much broken and eroded and covered on the high summits with 

 primeval forest, but the low-lying southwestern end consists of an 

 elevated coral-bearing limestone, which off Milford Bay and Pigeon 

 Point is fronted by one of the richest fringing reefs of the West Indies. 

 Dr. H. L. Clark found 75 species of echinoderms in this region, about 

 one-quarter of which are new to science. The fauna of Tobago, both 

 marine and terrestrial, shows distinct South American affinities and is 

 thus richer than that of the other West Indian islands, there being only 

 about 52 species of echinoderms known from Jamaica, while more than 

 one-third of the Tobago species are not found at Jamaica. Among the 

 most interesting echinoderms of Tobago is the crinoid Tropiometra, 

 which is common in water from 1 to 5 deep feet over Buccoo Reef near 

 Pigeon Point. 



Dr. Mortensen, of Copenhagen University, who accompanied our 

 expedition, raised this form, together with 9 other species of echino- 

 derms, and he found that Tropiometra passes through a stalked and 

 attached pentacrinoid stage. Dr. Clark found that it is remarkably 

 resistant to changes both in temperature and salinity, and this, 

 together with its commonness, and the ease with which the ripe eggs 

 may be obtained in March and April, should make it a classic object 

 for experimental work, Tropiometra being the only crinoid known to be 

 abundant in the very shallow water of the entire American region. 



Dr. Mortensen had been upon a world-tour, engaged in the study of 

 the development of echinoderms, of which he has reared a larger 

 number than have all other previous students of the group combined. 

 He found Tobago to be superior to any other single locaUty he had 

 previously visited for this purpose. Indeed, a limestone region is an 

 essential for success in rearing most marine invertebrates in aquaria 



