64 FOUNDERS OF OCEAKOGRAPHY 



being, as was supposed, " a group on the verge of extinction," 

 the stalked Crinoids were widely distributed and showed 

 scarcely any decrease in numbers since the times of their 

 ancestors in Mesozoic seas. Some of the Echinoidea 

 described in the report by Professor Alexander Agassiz 

 resemble the Ananchjrtidse of the Chalk, others are related 

 to the extinct Galerites ; while Cystechinus, with a thin 

 flexible test, recalls the Palaeozoic Palaeechinidee. Some of 

 the Echinothuridae, with flexible tests of imbricating plates, 

 had long been known as Cretaceous fossils, and the first- 

 found living representative, Calveria hystrix, of the " Porcu- 

 pine," was added to on the " Challenger " expedition by 

 various species of the remarkable allied genera, Phormosoma 

 and Asthenosoma. 



Many abyssal starfishes of primitive type were found, and 

 a number of these, in place of passing through a free larval 

 stage, have " direct " development, and keep their young for 

 a period in some form of nidamental pouch. Many new and 

 extraordinary deep-water Ophiuroids were added to know- 

 ledge, but it is perhaps in the Holothurians that we find the 

 most surprising novelties. A whole new abyssal group of 

 over fifty remarkable species — ^the Elasipoda — has been 

 made known in the report by Professor Hjalmar Theel, 

 nearly all found at depths greater than 1,000 fathoms and 

 ranging practically from pole to pole. They are charac- 

 terized, partly by primitive characters, such as the open 

 madreporic canal on the surface of the body, and partly by 

 adaptive characters fitting them to a life on the bottom ooze, 

 over which they crawl and upon which they feed. 



Amongst novelties in the Worms may be noted an 

 elaborately branched Syllis, spreading its numerous ramifica- 

 tions through the canal system of a Hexactinellid Sponge 

 dredged off the PhiUppines. Another noteworthy form was 

 Pelagonemertes, a pelagic Nemertine described by Moseley, 

 from the North Pacific and the Southern Ocean. 



The " Challenger " reports on Crustacea occupy nearly 



