  The concepts of linear Jaco graphs and Jaco-type graphs have been introduced
as certain types of directed graphs with specifically defined adjacency
conditions. The distinct difference between a pure Jaco graph and a Jaco-type
graph is that for a pure Jaco graph, the total vertex degree $d(v)$ is
well-defined, while for a Jaco-type graph the vertex out-degree $d^+(v)$ is
well-defined. Hence, in the case of pure Jaco graphs a challenge is to
determine $d^-(v)$ and $d^+(v)$ respectively and for Jaco-type graphs a
challenge is to determine $d^-(v)$. In this paper, the vertex in-degrees for
Fibonaccian and modular Jaco-type graphs are determined.
