A transition or tapered portion 50 extends from {HEAD ~ the portion} 48 to {TAIL ~ an enlarged portion}, shown as a spherical cap 52 
A transition or tapered portion 50 extends from { HEAD ~ the portion } 48 to { TAIL ~ an enlarged portion } , shown as a spherical cap 52
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH