152 RESEARCHES IN HELMINTHOLOGV AND PARASITOLOGY. 



species was the Tccnia soliian, but later experience would indicate 

 that the Tcenia mediocajicllata is the more common. The distinction 

 between the two had been observed only comparatively recently, so 

 that no doubt many specimens formerly attributed to the former 

 actually belonged to the latter. 



When the head is present the two species are readily distinguished. 

 The Tcsnia solium, whose larval form is found in the " mea.sle " of 

 pork, has the head provided with a crown of hooks. '/'tsnia niedio- 

 canc/lata, derived from beef and mutton, has a larger head, which is 

 unarmed. The ripe segments are also usually readily distinguished 

 in the two species. In the T. nicdiocanellata the ovaries are divided 

 into many more pouches than in T. solium. 



In Dr. Levick's case the man had been in the habit of eating raw 

 buffalo meat. In one of the specimens exhibited the suckers of the 

 head appeared as black spots, from the black pigment on their inte- 

 rior surface. The genital apertures were also black from the same 

 cause. In the other specimen the head appeared less black from 

 pigment about and around the position of the suckers, and the 

 genital apertures do not appear black. 



[November, 1878. No. 464. See Bibliography.] 



Oti Donax Fosser. — Prof. Leidy remarked that last July, while on 

 a visit to Cape May, N. J., he had observ^ed on the beach, near low 

 tide, east of the town, in many positions, vast numbers of the little 

 lamellibranch mollusks. Donax fosser, of Say. It is well named the 

 "Digger" from the ease and rapidity with which it digs its way 

 into the sand by means of its powerful foot. It lives in the surface 

 sand and is uncovered by the surf breaking on the shore, but in- 

 stantly buries itself again as the waves retire. In some places the 

 little Digger was so abundant that large patches reminded him ' ' of 

 barley grains lying on a matting floor," and they lay so thick as 

 actually to interfere with one another in the attempt to bury them- 

 selves. As indicated by Mr. Say, they present two varieties, one 

 in which the shell is white, the other in which it is straw-colored. 

 The shells generally exhibit an interior livid tint in three raj's, suc- 

 cessively widening from before backward. The rays are sometimes 

 feeble or nearly obsolete ; the anterior one is the most persi.stent 

 and the posterior one lea.st so. The siphons are long and actively 

 protruded and retracted, looking in their movements like wriggling 

 worms. The Digger affords a bountiful supply of food to shore 

 birds and fishes. 



As is so frequently the case with crowded communities, the Digger 



