132 BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



spines, each with a heavy half-wreath of crossed pedicellariae; the numerous 

 abactinal and superomarginal spines with thick wreaths of the same; one series of 

 small actinal plates wholly spineless and hidden under integument; mouth angle 

 primitive; two pairs of adambulacral plates in contact behind the rather large mouth 

 plates; adambulacrals diplacanthid ; large unguiculate straight pedicellariae may be 



present. 



Remarks. — The genus to which Lethasterias shows greatest superficial resemblance 

 is Distolasterias Perrier, of which I have examined three species: D. stichantha 

 (Sladen, genotype), D. robusta (Ludwig, as Stolasterias) , and D. nipon (Dbderlein, as 

 Asterias). 



The points of resemblance common to all species of Distolasterias and to Leth- 

 asterias are the small, spineless, immersed actinal plates in a single series; the dipla- 

 canthid adambulacrals; the rather short adoral carina; the similarity of the supero- 

 marginal and inferomarginal plates. 



But other, totally unrelated genera have a single series of actinals, and a short 

 adoral carina. On the other hand, the three species of Distolasterias have a common 

 form of crossed pedicellaria different from that of Lethasterias. This is a conservative, 

 reliable character. Lethasterias also has very numerous plates and spines. In two 

 nearly equal-sized specimens, D. nipon has 70 inferomarginal plates and L. nani- 

 mensis chelifera has 100; while as an index to the number of dorsolateral plates, 

 nipon has the equivalent of two or three dorsolateral series at base of ray while 

 chelifera has five. Lethasterias has a characteristic odontophore with two pits on 

 the outer border, as in the very different Meyenaster and Asirostole. 



LETHASTERIAS NANIMENSIS (Verrill) 



Plate 60, Figures 5, 5a; Plate 61, Figures 2, 2a-2e; Plate 62, Figure 3; Plate 64, Figure 1 



Asterias nanimensis Verhill, Shallow-water Starfishes, 1914, p. 105, pi. 61, figs. 1, la, 16 



(Asterias manimcnsis, err. typ.). 

 Distolasterias nanimensis, Fisher, Ann. and Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 258. 

 Lethasterias nanimensis, Fisher, Ann. and Mag. Nat. Hist., ser 9, vol. 12, 1923, p. 258. 



The type of this species, as figured by Verrill on Plate 61 of his well-known work, 

 was kindly forwarded to me by the authorities of the Ottawa Museum. The label 

 is as follows: "Geological Survey Dept. Canada, 1905, no. 19. Distolasterias chelifera 

 Ver., cotype." This specimen, as just noted, is figured as the type of nanimensis, 

 and it undoubtedly also forms the basis of the description. On page 187 Verrill 

 lists the same specimen as the cotype of chelifera, indicating certain artificial pecu- 

 liarities such as the stained and varnished surface. The measurements of this 

 specimen, as the type of nanimensis, are practically the same as those given on 

 page 185, for the cotype of chelifera. 



This specimen appears not to have been hardened before drying so that the 

 skin became somewhat macerated. The papular areas are slightly sunken and the 

 skeleton is rather plainly visible. Altogether it looks very unnatural. If any large 

 unguiculate pedicellariae were present, as is likely, at least in the actinal interradial 

 channels, these have sloughed off. Practically all the straight pedicellariae of the 

 adambulacral plates have disappeared. There are no oral pedicellariae. The viscera 

 have been removed through openings at the base of the rays. 



A well-preserved alcoholic specimen from station 3464, Straits of Fuca, due 

 south of Victoria, Vancouver Island, about on the international boundary line, 



