54 



In reply to a question from Dr. Storer, whether the 

 Ophiuridse were found at greater depths -than the Holothu- 

 ridse, Mr. Ayres stated that his observations did not indi- 

 cate the existence of such a law among the species of our 

 coast. 



Both families range from the level of the tide as far clown as 

 our researches have yet extended. Of the Hololhuridss, Synapta 

 is abundant at low water mark, and occurs from that to six or 

 feven fathoms, from which he had dredged various specimens ; 

 Sderodactyla and Cfdrodota both inhabit very shoal v/ater ; at a 

 little greater depth we reach Ciioieria and Psolus IcEVigatus, the 

 latter going as deep as to eighteen fathoms ; passing then across 

 very deep water as we leave the land and rising on George's 

 Bank, at the depth of thirty to fifty fathoms we find Botryodac- 

 tyla very abundant, with another species yet undescribed ; still 

 further out on the Grand Bank of Newfoundland we meet with 

 Stereoderma and Psolus phantapus (?) at about an equal depth. 

 Of the Ophiurid^, two species of Ophiocoma are abundant in 

 Massachuhctts Bay from low water mark to the depth of eighteen 

 fathoms ; but it is worthy of note that while O. aculeata is 

 exceedingly numerous at the latter depth in the inner parts of 

 the Bay, it is scarcely to be detected on the Middle Bank in no 

 deeper water, a much greater depth having intervened before 

 reaching that locality. From George's a few fragments merely 

 of OphiuridcE have been received, showing that they cannot be 

 abundant there, as many Star Fishes of other tribes are taken by 

 the fishermen. Two species of OphioJepis occur, one from the 

 littoral region, the other from the Banks of Newfoundland. 



This sliiiht survey is sufficient to show something of the habitat 

 of the two families. It seems in fact yet too early to establish 

 any general proposition in regard to it, since new facts are 

 daily brought to our notice, many of which directly contradict all 

 previously received opinions. This is true not only of the Radi- 

 ata, but equally so of other departments. Fishes universally con- 

 sidered littoral have been found at depths of sixteen, eighteen, 

 and twenty fathoms, and others still, one hundred and eighty 

 miles at sea, in forty fathoms. The Ophiuridae and Holothuridse 

 of George's, and the Grand Bank may probably yet be found 



