1 IS BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



chlora, however, since Professor Yerrill has used the name for the common 6-rayed 

 Leptasterias of the Alaskan coast, in spite of the fact that Brandt wiites that his 

 epiclilorn had live rays. 



The nam.' alveolata was given by Yenill to a specimen taken at Departure 

 Bay, British Columbia, ami now in the Ottawa Museum. It is one of the swollen- 

 i i \ ed variants, such as Plate 62, Figure 2, but with the spines as in Plate 63, Figure 1. 

 The papular areas are sunken, accentuating the skeletal mesh, since the specimen 

 was dried before being properly preserved. 



The specimen figured by Verrill (1914, pi. 26, figs. 1 and 2) as typical troschelii 

 belongs to forma alveolata. It is very similar to Plate 62, Figure 4, and has not 

 the peculiarities of the type of troschelii. Verrill's Plate 22 represents a very imma- 

 ture specimen from Juneau, Alaska. It is a young alveolata with considerable dis- 

 parity in size between major and minor abaotinal spines. The areolations are not 

 so distinct as in the foregoing specimen. This is characteristic, however, of many 

 young specimens, which pass through a stage in which they resemble forma troschelii. 

 The young of Pisaster ochraceus usually have acervate dorsal spines. Much fewer 

 adults are so characterized, so that the young are in many cases transiently forma 

 nodiferus. 



The type of Verrill's variety parvispina is a very immature alveolata which was 

 taken at Sitka. Its peculiarities are partly due to immaturity. Among examples 

 of troschelii and of alveolata having two sizes of dorsal spines, certain ones not infre- 

 quently have unusually slender minor spines, while the major spines are somewhat 

 less often quite slender. 



Forma alveolata is therefore much more inclusive than Verrill's variety alveolata. 

 This name has been adopted since Asterias brachiata Perrier, 1875, is invalidated 

 by A. brachiata Linnaeus. 



Most of the specimens which I collected or examined at Departure Bay, num- 

 bering several hundred, were accompanied by a commensal polynoid annelid, Halo- 

 sydna fragilis, which lives among the tube feet, usually at base of ray, or in the 

 actinostome. 



Forma ACANTHOSTOMA (Verrill) 



Plate 58, Figures 3, 3a, 36; 8, 8o-8c; Plate 59, Figure 36; Plate 64, Figures 2, 3; Plate 65; Plate 66, 



Figure 2 



Asterias aeanthostoma Verrill, 1909, p. 543, footnote. 



Evasterias aeanthostoma Verrill, 1914, p. 165, pi. 20, figs. 1 and 2; pi. 24, fig. 3. 



Plate 64, Figure 3, shows a typical specimen from Unalaska and Plate 66, 

 Figure 2, the actinal surface of the same; Plate 64, Figure 2, is one of the most 

 typical of the Tongass, Alaska, specimens. Plate 65, Figure 1, is a large slender- 

 rayed variant from Orcas Island, San Juan Islands, Wash., and Figure 2 a thick- 

 rayed specimen from Victoria. Plate 65, Figure 3, is an enlargement of a ray of 

 the Unalaska specimen. Plate 63, Figure 2, is a problematical variant from Tongass, 

 Alaska. Although taken with aeanthostoma, it and other specimens may perhaps be 

 more appropriately classed as very slender spined alveolata. 



Forma aeanthostoma intergrades with alveolata. It is not possible to place 

 (criain specimens definitely in either forma since they stand midway between. 

 Typical specimens differ from forma nlru4.it,, in having uniformly small abactinal 



