Marine Invertebrates 



SPONGES 



The vase sponge, Esperiopsis quatsinoensis, is common through- 

 out the islands. It washes up on the beach and eventually bleaches 

 out to a creamy-white color. In size and general shape, it re- 

 sembles a flattened ice cream cone. A large specimen from 

 Aiktak Island measured 28 centimeters from base to lip and was 

 30 centimeters wide. 



COELENTERATES 



HYDROIDS 



Abietinaria filicula is a small hydroid about 5 centimeters 

 long, resembling a feather. It is often washed up in tangles of 

 seaweed. 



Another hydroid, Thuaria robusta, has been collected in sea 

 otter scats. 



JELLYFISHES 



The common crystal jellyfish of the West Coast (Aequorea 

 aequorea) is observed almost daily after the first of July in the 

 Aleutian Islands. It is a transparent, lens-shaped medusa that, 

 at first glance, appears to have no organized structure, but closer 

 scrutiny will show a delicate central manubrium and a fringe of 

 fine tentacles. The body mass is firmer than that of the large red 

 jellyfishes and may be turned over readily in the hand. A few 

 specimens reach a diameter of 150 millimeters. 



Aurelia aurita is transparent, but it has a conspicuous struc- 

 ture in the center — a set of four yellowish-brown gonads arranged 

 like the leaves of a four-leafed clover. Of the two species, Aequorea 

 appears much more frequently during the summer. 



Cyanea capillata is one of the large, trailing, red jellyfishes 

 frequently seen from July to September, especially in the calmer 

 bays. The rim of the medusa is divided into eight pairs of short 

 lobes, or a total of 16 lobes. Each lobe has a medial notch about 



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