d3.js - Topojson missing outside boundaries -

when rendering topojson, i'm missing outside boundaries of states.

for example, view of south looks this:

instead, need outside boundaries filled.

my style map follows:

.state-boundary {         stroke: #00001d;         stroke-width: .5px;         fill: white;         stroke-linejoin: round;         stroke-linecap: round;       } 

the geojson looks follows prior conversion topojson:

my d3 follows:

svg.append("path")         .datum(topojson.mesh(topology, topology.objects.south, function(a, b) { return !== b; }))         .attr("d", path)         .attr("class", "state-boundary"); 

so, matter of changing mesh method. don't understand difference, maybe can chime in:

svg.append("path")         .datum(topojson.mesh(topology, topology.objects.south))         .attr("d", path)         .attr("class", "state-boundary");