MARINE BIOLOGICAL STATION AT PORT ERIN. 59 



tests of imbricating plates, had long been known as Cretaceous 

 fossils, and the first-found living representative, Calveria 

 hystrix, of the " Porcupine/' was added to on the " Challenger " 

 expedition by various species of the remarkable allied genera. 

 Phormosoma and Asthenosoma . 



Many abyssal star-fishes 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 

 knowledge, 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 characterised, 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 Bi/llis, spreading its numerous ramifica- 

 tions through the canal system of a Hexactinellid Sponge 

 dredged off the Philippines. 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 

 one fourth of the whole, and describe nearly 1,000 new species, 

 some of which show remarkable modifications induced by 

 life at great depths. Certain of them are totally blind, and 

 others have eyes that are profoundly degenerate in their 

 minute structure and are probably useless as organs of sight. 



Amongst the Pycnogonida, or Sea-Spiders, were some 

 gigantic forms of Colossendeis measuring about 2 feet across 



