ECHINODERMS. 



29 



be due to differences in habitat. The starfishes from Vineyard Sound and Marthas Vineyard, 

 for cxanii)le, may liave come from different depths of water, and so, too, may the two marked 

 as from the East Indies. Small impurities in the specimens analyzed may also account for 

 some irregularities. The analj^ses by L. Schmelck,'^ of starfishes from the North Sea, are, how- 

 ever, not so easy to explain. His data are as follows: 



1. AreasUr teimupinus. Station 10; latitude, 01° 41' N.; longitude, 3° 19' E.; depth, 402 meters; bottom tera- 

 porature, 6° C. 



2. Arcaster Unuispinus. Station 25; latitude, 63° 10' N.; longitude, 5° 25' E.; depth, 179 meters: bottom tem- 

 perature, (5.9° C. 



3. Astropecten andromeda. Station 10; details under No. 1. 



Schmelck's analyses of starfishes. 



SiO, Trace. 



ALO3 1 Trace. 



Fe'A 0.31 



MgCO, , 9.36 



CaCO, I 74.11 



CaSO^ (?) 



P2O5 Trace. 



Organic matter 16. 23 



Trace. 



Trace. 



0.60 



9.24 



78.92 



1.00 



Trace. 



10.24 



100. 00 



100. 00 



7.09 



.65 



.37 



8.55 



()4.48 



.83 



Trace. 



13.83 



95.80 



Schmelck's analyses reduced. 



Nos. 1 and 3 of this group of analyses represent the same locaUty and temperature. If 

 the excessive and surely extraneous silica in No. 3 is rejected and the analyses are recalculated 

 to 100 per cent the figure for magnesium carbonate becomes 11.41, nearly that for No. 1. iVll 

 the percentages given for magnesium carbonate are higher than the temperatures would lead 

 us to expect, but they still fall far below the highest ten in our table. A general tendency to 

 regularity as regards temperature is evident, but it is perhaps not invariable. 



4. OPHIUE.ANS OB BRITTLE STARS. 



The following data relate to the composition of the ophiurans, as distinguished from the 

 ordinary starfishes. 



1. Gorgonocephalus arcticus Gray. Off (^ape Cod, Mass.; about latitude 42° N. 



2. Gorgonorephahis caryi Lyman. Alaska. 



3. Ophioglypha sarsii Lutken. Albatross station 2176; latitude, 39° 32' 30" N.; longitude, 72° 21' 30" W.; depth, 

 553 meters; bottom temperature, 5° C. 



4. Ophioderma driereum Muller and Troschel. Ensenada Honda, Culebra Island, east of Porto Rico; about lati- 

 tude 18° 20' N. 



5. Ophiomyxaflaccida Say. Pigeon Point, Tobago, British West Indies; latitude, 11° 25' N.; shoal water, close in 

 shore; temperature, 28° C. Adult specimen. 



« Schmelck, L., Norske Nordhavs Exped., No. 28, p. 129, 1901. 



