t^ 



The Nautilus. 



Vol. XXII. NOVEMBER, 1908. No. 7. 



A GIGANTIC SOLEMYA AND A NEW VESICOMYA. 



BY WILLIAM HEALEY DALL. 



In the course of the Albatross dredgings in the Philippines during 

 the period in which Dr. Paul Bartsch of the U. S. National Museum 

 was attached to the scientific staff of that vessel, a dredging was 

 made between the islands of Ticao and Masbate in 600 fathoms. 

 Among the objects obtained from this haul (station 5215) was the 

 fresh shell of a Solemya, which, compared with the previously known 

 species, may be regarded as enormous. Nothing remained of the 

 soft parts which had evidently been but recently lost. 



Solemya (Acharax) bartschn n. sp. 



Shell subcylindrical, gaping at the ends and along the base, cov- 

 ered with a strong polished black periostracum which extends over 

 the margins, being continuous over the dorsal ])ortion between the 

 valves and produced beyond the edges of the shelly portion, basally 

 about 40, in front about 35, and behind about 15 millimeters. In 

 life this produced periostracum, undoubtedly covers and protects' the 

 portions of the surface of the animal not sheltered by the calcified 

 valves ; the margin at the anterior end is not split into strips cor- 

 responding lo the radii of tlie shell as in the large American species 

 of the group, but preserves ils continuity and is contracted margin- 

 ally so that in life it must closely cover the whole anterior end of the 

 animal, in a dome-like manner. Internally the ligament is wholly 



