NO. 2207. WEST AMERICAN MELANELLID MOLLVSKS—DARTSCH. 353 



prohoscis is a spherical muscular stomach, and the intestine ascends 

 into the spire of the shell, where it becomes attached to the liver, 

 which, in the present species, is of an orange colour, 



"Mr. Cuming found this elegant parasite burrowed in different 

 parts of the rays of the oral disk of Asterias Solaris, Gray, where it is 

 almost hidden from sight, so deeply does the animal penetrate into 

 the substance of the Starfish, in which it makes a comfortable cyst for 

 itself, wherein it most probably turns by the aid of its rudimentary 

 foot. All the specimens infested with Stiliferi appeared to be in the 

 best health, though there is reason to believe that these Mollusca feed 

 upon the juices of the Starfish. With that instinct of self-preserva- 

 tion imparte'd to all parasites whose existence depends upon that of 

 their nidus, the Stilifer, like the Ichneumon among insects, appears to 

 avoid the vital parts; for in no instance did Mr. Cuming find it em- 

 bedded anywhere save in the rays, though some had penetrated at 

 their base and very near the pelvis. Wlien extracted the older shells 

 have much the appearance of a milky, clouded, glass bubble; the 

 younger shells are of an unclouded transparency." 



Genus MUCRONALIA A. Adams. 



Mucronalia A. Adams. Ann. Mag. Nat. Hist., ser. 3, vol. 5, 18G0, p. 301. Type 

 Mucronalia bicincla A. Adams. 



Melanellids with mucronate apex, cylindric postnuclear spire and 

 with the inner lip not appressed or adnate to the attenuated base of 

 the preceding whorl. 



MUCRONALIA? BATHYMETRAE Dall. 



Plate 49, fig. 3. 



Stilifer {Mucronalia) balhymetrae Dall, Bull. Mus. Comp. Zool., Cambridge, 

 vol. 43, 1S08, No. 6, pp. 317, 318. 



" Mucronalia? Hartlaub, Bull. Mus. Comp. Zool., Cambridge, vol. 27, No. 4, 

 1895, p. 146, pi. 4, fig. 25. 



"On a species of Bathymetra, dredged by the U. S. S. Albatross, at 

 station 3381, off Malpelo Island, Gulf of Panama, in 1,772 fathoms, 

 mud, bottom temperature 37.2° F. 



"In Hartlaub's account of the crinoids of the Albatross above cited, 

 he mentions and figures a species, referred by E. von Martens to 

 Mucronalia, parasitic on a species of crinoid, later referred by Clark 

 to Bathymetra. The specimen has not yet been submitted to the 

 writer, and the figure is insufficient to base a specific description 

 upon. It resembles Stilifer (Mucronalia) thomasiae Sowerby, of the 

 West Indies, and is fixed to one of the arms of the crinoid. If the 

 species is hereafter recovered, it might appropriately take the specific 

 name of bathymetrae." 



I have not seen a specimen of the species and quote the published 

 text and figure. 



77403— Proc. N. M. vol. 53—17 23 



