"[T]he development of software for specific use as a teaching aid in theoretical . . . morphology is as essential as leading-edge research to ensure the continued development of this field."

The code given in this paper was written by two theoretical morphologists (Raup, McGhee) in close interaction with a bryozoan biologist (McKinney) and has been produced by an evolutionary process of trial-and-error in writing algorithms that would best simulate the organic forms actually seen in helical bryozoans in nature. We hope that it will not only stimulate further research in the analysis of the evolution of helical colony form, but that it will also be used as a teaching aid in illustrating the analytical techniques of theoretical morphology. Specifically, future instructors might begin with the existing code, and seek to even more closely model the form seen in helical bryozoans in a series of laboratory exercises. One obvious aspect of bryozoan form that has not been simulated at present is the presence of dissepiments – cross-bars between the branches in the colony. Another instructive approach would be to explore just how far the limits of the program could be pushed in producing nonexistent form. For example, the maximum values of BWANG shown in Figure 1 stop at 90 degrees – yet the program is capable of simulating angles that exceed that value.

Yet another future possible avenue of both research and pedagogical significance would be to see if similar simulations of form could be produced with totally different algorithmic approaches, such as the usage of L-systems (Prusinkiewicz and Lindenmayer 1996; for a detailed discussion of the potential uses of L-systems in theoretical morphology see McGhee 1999). L-systems have been used to produce very realistic simulations of branching-form in plants, and we see no reason why the approach could not also fruitfully be applied to branching-form in animals. Lastly, it might also be instructive to see if the algorithms could be simplified by using existing modeling software such as Mathematica (Wolfram 2002).