134 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



spec." Reeve, Conch. Icon., vol. 20, 1878 (on title page), 



Auricula, sp. 47, pi. 6, fig. 47. "Hab. Jamaica." 



Melampus tabogensis (C. B. Adams), Pfeiffer, Monogr. Auric. Viv., 



1856, p. 47. von Martens, Biol. Centrali-Americana, Moll., 



1900, p. 560, pi. 43, fig. 8. Panama. von Martens, Sitz. 



Ges. Naturf. Freunde zu Berlin, Jahrg., 1902, no. 6, p. 137. 



Cocos Island. Biolley, Mollusques de L'lsla del Coco. 



Mus. Nac. de Costa Rica, 1907, p. 24. "Est abondant sur les 

 plages sablonneuses de la Baie de Wafer et a rembouchure de 

 r Arroyo del Genio." 



The members of the 1905-1906 Expedition (Calif. Acad. Sci.) ob- 

 tained about 100 specimens of this dark reddish brown species. It is 

 a much heavier and slightly larger species than trilineatus and is usually 

 more highly polished. The columella usually bears not more than three 

 teeth, the lovrermost of w^hich is very thick and heavy. 



Melampus trilineatus (C. B. Adams) 



Auricula trilineata C. B. Adams, Ann. Lye. Nat. Hist. New York, vol, 



5, July, 1852, pp. 436, 543. "Panama, 1 spec." Carpenter, 



Rept. British Assoc. Adv. Sci. for 1856 (issued 1857), p. 275. 



Melampus trilineatus (C. B. Adams), Pfeiffer, Monog. Auric. Viv., 



1856, p. 44. von Martens, Biol. Centrali-Americana, Moll., 



1900, p. 559, pi. 43, fig. 7. Panama. 



The members of the California Academy of Sciences Expedition of 

 1905-1906 secured a number of specimens of this species estimated at 

 5,000. All of these are rather smaller than the dimensions which Adams 

 gave for his single specimen but they do not differ greatly from the one 

 figured by von Martens. Naturally very great variation is displayed in 

 so large a series. Light color bands vary from none to as many as five; 

 there are usually four or five teeth on the columella, the lowermost one 

 being the largest. One of the most constant characters in the lot is 

 the presence of a series of spiral threads on the spire above the periphery. 

 These are not present on the dark reddish brown species which we 

 refer herein to tabogensis, and do not seem to be present on a spirally 

 banded beach-worn shell from Panama which Mr. A. M. Strong has 

 identified for us as trilineatus. A considerable number of the Cocos 



