DALL: MOLLUSCA AND BRACHIOPODA. 339 
way up the cone of the shell and distally project prominently beyond the periphery 
of the base. The characteristics of the anatomy are described by Dr. Pelseneer, 
in a paper following the description above cited, from which it appears that the 
animal is without eyes, possesses two very short tentacles, and on the right side 
from the base of the right tentacle extends a rather long, pointed verge, grooved 
on the outer ventral side. The mouth contains a single unpaired jaw, and a long 
radula with the formula 1*4 *0* 4*1, the uncinal tooth being plate-like, and the 
third lateral larger than any of the others and furnished with a strong cusp. The 
rhachidian tooth is absent, The middle of the surface of the foot is produced or 
protruded, taking the form of the excavation upon which the animal rests. There 
are no gills either pallial or ctenidial, and Dr. Pelseneer believes that respiration is 
performed, as in Lepeta, by the surface of the mantle. The nervous system recalls 
that of the Docoglossate Limpets, there are two otocysts, each containing a single 
otolith. 
Tho animal appears, unlike most of the true Limpets, to be hermaphrodite, pos- 
Sesses a heart with a single ventricle, two renal organs, and a large hepatie gland. 
Dr. Pelseneer concludes that the family belongs in the Docoglossa, to which so 
many of the anatomical charaeters point. 
Desiring to have the most careful examination made of the Pacific species, 
specimens were sent to Dr. Johann Thiele, of the Royal Zoological Museum at 
Berlin, well known from his anatomical researches on Mollusoa.! It will be noted 
that the B. pacificum is considerably larger than the Atlantic form, giving a better 
Opportunity to the anatomist for studying the minor details. 
Bathysciadium pacificum Darr, n. sp. 
Plate 9, figures 1, 3, 7. 
Shell small, circular, conical, in every case with the apex eroded buf evidently 
central or slightly in advanoe of the centre; color whitish, with a smooth, polished, 
concentrically faintly striated surface, a rather thick chalky layer being originally 
Situated on a porcellanous inner coat; on the exterior the periostracum has a rather 
remarkable disposition and character ; there are about twenty radial lines upon the 
Surface on which the periostracum is developed in long fringe-like hairs which are 
not a continuous series but constitute a line of successive whorls extending some- 
what beyond the margin of the shell; these are divided usually into groups of five 
radii, the lateral radii have the whorls of hairs extremely long and abundant, es- 
Pecially beyond the margin, where, when the animal raises itself to admit water 
and food between the shell and its situs, these fringes cloak the sides so no sedi- 
ment can enter between the shell and its pedestal; the anterior and posterior 
groups of radii have the whorls short, not extending much beyond the margin, 
thus by ciliary action an anterior incurrent and posterior excurrent flow is doubt- 
1 Dr, Thiele’s results will appear separately in the Bulletin Mus. Comp. Zoólogy. 
