Characteristics

1. Shell
   1. Shell V-shaped.
   2. Shell surface smooth.
   3. Basal shelf present.
   

   Figure. Dorsal and ventral views of a shell of C. glacialis stained with methylene blue. Photograph by R. Young.

2. Color
   1. The oral surface of the arms and web with distinctive appearance. "...circumoral ring of white patches, each of which lies astride an arm. Between this ring and the mouth, the web was bright reddish purple; peripherally and beyong the ring it was of an intense bluish purple. The pattern and coloration are extremely vivid..." (Robson, 1930).
   

   Figure. Oral view of G. glacialis showing pigmentation pattern. Photograph from Vecchione, et al., 1998.

Comments

Additional features of the description of C. glacialis can be found here.

C. glacialis differs from C. hochbergi in having a smooth rather than a rugose shell, a thick rather than a thin mantle septum, a peculiar pattern of pigmentation on the oral face of the arms and web and a caecum that is much larger than the stomach. Unfortunately, differences in fixation and physiological state could account for some or all of these apparent species characteristics.