NO. 4 



ziesenhenne: new eastern pacific sea stars 



205 



From Ltiidiaster dawsoni (Verrill) of Alaskan waters this species 

 differs as follows: 



Luidiaster dawsoni 



Abactinal paxillae with short spines 

 surrounding the central spine. 



Paxillar spinules long, sharp, dis- 

 tinct. 



Large, prominent, circular pecti- 

 nate pedicellariae on actinal and 

 abactinal surfaces, composed of 

 2 or 3 combs of 12 or less long, 

 heavy, stronglj^ recurved spin- 

 ules, almost L-shaped. 



Adambulacral furrow spines 5-7. 



Adambulacral actinal spines 2-4. 



Actinostomial oral spines 6-8. 



Suboral spines 7-10. 



Muscle tendon attached to 7th or 



8th ambulacral ossicle and 3rd 



superomarginal. 



Madreporite in young nearly 



touching superomarginal. 

 Papulae absent from center of disk. 



Luidiaster calif ornicus 



Abactinal paxillae with long spines, 

 surrounding the central spine 

 and often equal in length. 



Paxillar spinules short, blunt, 

 granulelike. 



Small, inconspicuous, flat pectinate 

 pedicellariae confined to actinal 

 surface, composed of 2 combs of 

 7 or less short, broad, blunt, 

 straight spinules. 



Adambulacral furrow spines 3 or 

 4. 



Adambulacral actinal spines 2 or 3, 

 rarely 4. 



Actinostomial oral spines 5 or 6. 



Suboral spines 3-5. 



Muscle tendon attached fanwise to 

 9th or 10th ambulacral ossicle 

 and 2 or 3 lateral tendons to 

 3rd, 4th, 5th, or 6th superomar- 

 ginal. 



Madreporite more than its diame- 

 ter from superomarginals. 



Papulae present on center of disk, 

 except young. 



This species is distinct from Luidiaster horridus (Fisher) of the Ha- 

 waiian Islands as follows: 



Luidiaster horridus 

 No pectinate pedicellariae. 



Luidiaster calif ornicus 



Pectinate pedicellariae present ac- 

 tinally. 



Oral plates with 3 enlarged spin- Oral plates with 3-5 actinal promi- 

 ules. ntnt spines. 



