109 



of food particles from the water, transportation of the same to the mouth, and 

 ingestion (Werner, 1959). 



Evidently, larvae of sea stars do not possess chemoreceptors, which would 

 discern the quality of the food ingested, since they ingest not only unicellular 

 algae but also coal particles (Dautov, 1979). The perioral depression or the 

 oral field participates in the capture of food but the main trapping apparatus 

 is the ciliated bands — the small preoral band, the postoral edging the entire 

 body (except the preoral plate), and the adoral band bordering the oral open- 

 ing. The preoral band passes into the medioventral and the two preoral pro- 

 jections (arms), while the postoral band passes into the mediodorsal and 

 paired postoral, posterolateral, posterodorsal, and anterodorsal projections 

 (arms) (see Figure 71). The degree of development of any projection is 

 considered when determining the species affinity of a larva. In some species 

 of sea stars the ciliated band is barely discernible on the projections (arms) 

 (Asterias, Pisaster, Pycnopodia); in others (Patiria, Luidia) it is quite distinct 

 (Strathmann, 1971). The ciliated band reaches the maximum length in the 

 bipinnaria oi Luidia (Figure 72) (Meek, 1927; Strathmann, 1971; Wilson, 

 1978). The adoral band forms two strands passing along the ventral side of 

 the esophagus and forms a long stretched loop. In the larvae of sea stars the 

 entire outer surface of the body is armed with individual cilia. 



pocb 



Figure 70: Bipinnaria oi Patiria miniata (from Strathmann, 1971). 

 pocb~postoral ciliated band; prcb — preoral ciliated band. 



