KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 157 



CoisfPAEisoNS. — This species greatly resembles Gymnodinium nmpliora. The 

 relative proportions of cpifone and liypoeone, however, tend to rank it with 

 Ampliidinium, though on rather arbitrary grounds. It and ^1. cucurbita are 

 the most highly specialized members of the genus and of a t\'pe closely paral- 

 leling the highest specialization of the genus Gijinnodiniuiii. The ectoplasmic 

 struetiire in .4. rasciihiiit lacks the high degree of development found in many 

 of the species of the subgenus PacJiydiniunt in Gymnodinium, but is clearly of 

 a similar nature. In its cytoplasmic structure it resembles A. cucurhita and 

 Gymnodinimn dogieli and G. pachydermatum. In coloring it is one of the most 

 striking species of the genus. 



