502 REPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



The color is chocolate-brown, with bright red, lignlate, dorsal brauchiae 

 on the anterior third of the body. The two large tentacles exceed in 

 length three times thebreadth of thft body ; they are often coiled up, and 

 are greenish in color. This worm is three or four inches long. 



A large purple Meckelia {M. lurida V.) was dredged in two localities. 



Among the Mollusks tliere are but few species that are characteristic 

 of these bottoms, and i^robably none that are peculiar to them, unless 

 some of the Ascidians should prove to be so. The Molgula arenata (p. 

 426, Hate XXXIII, fig. 251) is often common even on loose siliceous 

 saud and gravel, with which it forms a coating over its body. The 

 Molgula producta was dredged in some numbers on a bottom of fine 

 sand, with some mud. The integument is thin, transluceut, closely 

 covered with a layer of fine saud ; the tubes are transparent, whitish or 

 flesh-color, sometimes jjink at theends; anal tube with four, and branchial 

 with six, flake-white, longitudinal stripes, and often with a circle of flake- 

 white spots at the base outside, and other spots withio. The anal ori- 

 fice is square, but the branchial is either subcircular or squarish, in 

 expansion, and destitute of distinct lobes or papillae, in this respect dif- 

 fering from all the other species of the genus. The branchial tube is 

 generally a little the longest, and both of them are somewhat tapered* 

 with a swollen base. 



The Glandida arenicola is another nearly globular Ascidian, which lives, 

 like the two preceding, free in the sand, and covers itself with a closely- 

 adherent coating of sand. This species grows to be about half an inch 

 in diameter, and can easily be distinguished from the last by its much 

 smaller tubes, both of which have small square orifices, and by its thicker 

 and (irmer integument, in which the saud appears to be somewhat im- 

 bedded. At the base there are some slender fibers for anchoring it more 

 securely in the sand. This was dredged by Mr. Prudden, off Cuttyhuuk 

 Island, in 1872. Messrs. Smith and Harger dredged it in great abun- 

 dance last year on St. George's Bank, on a bottom of clear siliceous sand, 

 in 28 fathoms. Dr. Dawson has also dredged it in Murray Bay, in the 

 St. Lawrence Eiver. It is, therefore, a decidedly iiorthern species. 



Another species of Gland ula also occurred on the true sandy bottoms. 

 The specimens of this were all small, mostly less than a fifth of an inch 

 in diameter, and the integument was densely covered by rather coarse 

 and very firmly adherent grains of sand, in several layers ; the sand 

 completely concealed the tubes from view in all the specimens observed* 

 and it was not sulBQciently studied while living to afford an accurate 

 description. 



The Bryozoa and Hydroids that are found on the sandy bottoms are 

 mostly attached to dead shells and small stones that are scattered over 

 the surface. 



Of Echinoderms several species occur on the hard bottoms of fine* 

 compact sand, or sandy mud, but most of these are more at home on 

 rocky bottoms. 



