I^ulmonifera of 3Iain&. 35 



gular spectacle is revealed in watching the tremulous movements 

 of these otoconites, continually crowding toward a common cen- 

 ter, not one being displaced, thougli, when the agitation finally 

 ceases, they become scattered along the Walls oF their enclosure,. 



In the third embryo, the ocular dots were distinctly visible, the 

 inantle protruded over the edge of the shell which had attaine<i 

 the growth of one whorl and a half. In this the lingual membrane 

 Was formed, though the whole maiss of thie animal seeYned to be 

 nothing but cells of various sizes ; the lingual membrane con* 

 tained only twenty- seven rows of plates, each roW having nine 

 plates. (I'late 1, Fi^, 12.) 



In the most Inatiired etobryo, the shell had attain<ed the gwWth 

 ■of two volutions; the superior tentacles were conspicuous^ and the 

 crenulations of the disk distinctly marked. The lingual mem- 

 brane in this had seventy rows of plates, with nineteen plates in 

 <a row. ■{Phoffie 1, Fi-g. 11.) 



These embryos seemed to fill the Wppei* portion of the parent 

 shell completely, and when born were as large as the aperture of 

 the adult shell. Several of these embryos were placed in a watch 

 glass Blled "With Water to faclliate examinations ; after being in 

 this condition, submerged for nearly thirty hours, I found them to 

 be still alive, as their hearts could be easily seen pulsating about 

 forty times per minute, and the body when irritated with the 

 point of a needle speedily contracted. 



The general anatomy of this species appears to difier in no 

 respect from allied species described by Leidy. The ganglionic 

 masses, {Plate 1, Fig. 5,) differ somewhat in their respective 

 sizes from those figured by Leidy, in Binney's Monograph, Vol. 

 1. The auditory capsules were quite large, and the otoconites 

 vibrated a long while after the ganglia had been removed from 

 the animal. The supra-oesophageal and sub-oesophageal' ganglia, 

 appeared to be connected by a single commissure on each side. 



The glottidium, or buccal body is aa oval shaped solid muscular 

 organ, forming the anterior portion of a very long oesophagus. 



The buccal plate is a wide, arcuated lamina, transversely and longitudinally 

 striate, corneous in texture, and, inserted just within the upper lip, its cutting 



