174 THE APODOUS HOLOTHUBIANS 



CAUDINA ARENATA. 

 PLATE X, FIGS. I, 2, 11. 



Chirodota arenata Gould, 1841, p. 345. 



Chirodota arenata Ayres, 1852a, p. 143. 



Caudina arenata Stimpson, 1853, p. 17. 



Caudina arenata Gerould, 1896, pp. 17-74; pis. in-x. 



LENGTH. 100-175 mm., rarely up to 250 mm.; caudal appendage usually 

 about 35-40 per cent of total length. 



COLOR. In life, pink to purplish; in preserved specimens, milky white to 

 pale brown, usually grayish. 



DISTRIBUTION. Reported from Newport, Cuttyhunk and Vineyard Sound, 

 Chelsea Beach, Revere Beach, and Massachusetts Bay (Gould, Pourtales, Ver- 

 rill, Kingsley, Gerould, et al.) ; Grand Manan (Ludwig) ; Milne Bank, North- 

 umberland Strait and Pointe du Chene, New Brunswick (Whiteaves). 



REMARKS. Although this species has been taken in large numbers at Revere 

 Beach, Mass., and in smaller numbers at Newport, R. I., and Chelsea Beach, 

 Mass., nearly all these specimens have been picked up on the shore after severe 

 storms. Few specimens have ever been dredged. Gerould 's ('96) explanation 

 of this is undoubtedly correct; the animals live buried in rather firm sand, only 

 the tip of the tail being at the surface, so that an ordinary trawl or dredge does 

 not reach them; but, as they live in comparatively shallow water (1-35 meters), 

 a heavy sea gradually washes them out of the sand and casts them upon the 

 shore. Gerould 's admirable paper is a complete account of all that we know 

 about this species. 



CAUDINA ALBIOANS. 

 PLATE X, FIG. 12. 



Trochostoma albicans Theel, 1886a, p. 44; pi. xi, fig. 3. Calcareous particles, pi. 



in, fig. 2. 



Trochostoma allicans var. glabra Theel, 1886o, p. 46. 

 Caudina arenata var. armata Theel, 1886&, p. 17. 

 Caudina arenata var. armata Gerould, 1896, p. 19. Calcareous particles, pi. in, figs. 



34-37. 



LENGTH. 75-115 mm., of which 20-35 are caudal appendage. 



COLOR. In preserved specimens, grayish or whitish. 



DISTRIBUTION. Reported from off the east coast of the United States be- 

 tween Cape Cod and Cape Hatteras, in 1,600-2,235 m. (Theel, Clark) ; near 

 New Zealand, 1,260 m. (Theel) ; off coast of Senegal, 3,200 m. (R. Perrier), and 

 Gulf of Bengal, 486-738 m. (Koehler and Vaney). 



REMARKS. It is only with the greatest hesitation that I venture to unite two 

 species, placed by so careful a worker as Theel in separate genera; but I am 



