NUDA 



423 



species are scarlet or carmine red and dirty brown or brownish 

 yellow. They are from 1 to 2 centimetres in diameter. 



CLASS II. NUDA 



Ctenophora without tentacles. 



Fam. Beroidae. Beroe, the only genus of this family and 

 class, differs from other Ctenophora in several important par- 

 ticulars. There are no tentacles, and the stomodaeum is so large 

 that the body-form assumes that of a thimble with moderately 

 thick walls. The infundibulum is small. The paragastric and 

 longitudinal canals give rise to numerous ramifications which 

 form a network distributed throughout the surface of the body. 

 The statolith is unprotected by a dome, and the polar fields are 

 bordered by a number of small branching papillae. The eight 

 ribs extend for nearly the whole length of the body. Beroe is 

 almost cosmopolitan, and is frequently found at the surface of 

 the sea in great numbers. B. ovata is found off the Shetlands, 

 Hebrides, and west coast of Ireland, but is rare on the east coast 

 of the British Islands and in the English Channel. At Valencia 

 it is common in August and September, and sometimes reaches 

 the great size of 90 mm. in length by 50 mm. in breadth. It is 

 usually of a pale pink colour. 



Appendix to Ctenophora 



Hydroctena salenskii has recently been discovered by Dawy- 

 doff l floating with the Plankton off the island Saparua in the 

 Malay Archipelago. It is claimed to be a connecting link 

 between the Ctenophora and the Medusae of the Hydrozoa. 



In external features it is like one of the Narcomedusae, 

 having a transparent jelly-like bell with a wide bell-mouth 

 guarded by a velum (Fig. 184, V). There are only two simple but 

 solid tentacles (t), provided with tentacle-sheaths, but inserted 

 on opposite sides of the bell not on the margin, but, as in the 

 Ctenophore, at a level not far removed from the aboral pole. 

 At the aboral pole there is a minute pore surrounded by a high 

 ciliated epithelium bearing an orange pigment. This leads into 



1 Zool. Anz. xxvii. 1904, p. 223. 



