Beroe cucumis Fabricius 1780  Common name(s): Melon comb jelly, Northern comb jelly, Beroe comb jelly
Synonyms:
Phylum Ctenophora Class Nuda  Order Beroida  Family Beroidae
	Beroe cucumis, about 4 cm long, captured at night from the Cornet Bay docks by Jamie Fields.
	(Photo by:  Dave Cowles, July 2026)

Description:Beroe is the only genus in the Ctenophore Family Beroidae, Order Beroida, and Class Nuda. All members of Class Nuda (that is, genus Beroe) have no tentacles. B. Cucumis is oval (like a watermelon, short cucumber, or blimp). Its cross-section is generally circular or nearly so, though it can be slightly flattened. Its length is up to about 10 cm. Its eight comb rows (called ctene rows) start at the aboral end. Some of them extend about halfway to the mouth end, while the rest extend about 2/3 of the way. It often has a translucent pink or lilac color, especially near the ctene rows and mouth (photo), or it may be colorless. The eight meridional canals from the gut have some side branches which are visible through the surface and do not anastomoze with each other to form an extensive network. 

How to Distinguish from Similar Species:  Ctenophores which are not in Class Nuda have at least some tentacles. They also have a sack-like body. While This species has a pink or lilac colorration, Beroe sp. has brownish spots and B. abyssicola is a strong red, purple, or black color. 

Geographical Range:  Alaska to California

Depth Range:  Surface to 400 m

Habitat:  Pelagic

Biology/Natural History:  This species is a predator on other ctenophores and salps. It is famous for consuming the ctenophore Pleurobrachia. It has a large mouth and can swim rapidly. It is said to be luminescent. While swimming, Beroe beats its ctene rows in a metachronal pattern (waves of beating passing sequentially along the ctene row) in a retrograde fashion: It swims mouth forward (photo), and as tit swims forward, the waves of beating proceed from the posterior (aboral) end to the anterior (mouth) end.

References:

General References:
  Harbo 2022
  Kozloff 1993
  Wrobel and Mills 1998

Scientific Articles:
 

Web sites:

General Notes and Observations: Locations, abundances, unusual behaviors:

In this view Beroe is swimming towards the camera, showing its large open mouth. Photo by Dave Cowles, July 2026


Here Beroe is swimming around a dish toward the left. The increased coloration near the ctene rows and mouth can be seen, as can the ctene rows of different length. Photo by Dave Cowles, July 2026. Dimensions shown are millimeters and centimeters.

Authors and Editors of Page:
Dave Cowles (2026):  Created original page
CSS coding for page developed by Jonathan Cowles

Salish Sea Invertebrates web site provided courtesy of Walla Walla University