238 RITTER 



CYNTHIA VILLOSA Stimp. 



Cynthia villosa Stimpson, Proc. Acad. Nat. Sci., Phila., Vol. 16, p. 160, 

 1864. — Herdman, Trans. Liverpool Biol. Soc, Vol. xii, p. 258, figs. 7- 

 II, pi. XII, 1898. 



Herdman has recently described in detail this species, which Stimp- 

 son characterized by its external features only. The only serious 

 difficulty in identifying the Alaskan specimens now under consideration, 

 with the Puget Sound forms is in the number of folds of the branchial 

 sac. According to Herdnian, the latter possess eight on each side, and 

 his statement is confirmed by the examination of some large specimens 

 from Puget Sound, undoubtedly belonging to the same species, and 

 which were sent me by the Young Naturalists' Club of Seattle. The 

 Alaskan specimens, on the other hand, possess only six, with rudi- 

 ments of a seventh. These individuals are all small however, the largest 

 being only I3 mm. high by 12 mm. deep, and 8 mm. thick; and one 

 specimen of about the same size among those from Puget Sound has, 

 so far as I am able to determine, only six on each side. I deem it 

 probable therefore that this difference in the number of folds is due 

 to difference in age. There is some difference in the spines also, 

 these in the Alaska specimens being somewhat shorter, and more in- 

 clined to an arrangement in groups on papillae of the test. As a rule, 

 however, they are neither in groups nor on papillae ; so this differ- 

 ence is not constant. Herdman has fully discussed the relationships 

 between the echinated species of the genus that were known at the 

 time of his writing. Since then, however, Hartmeyer, 1899, has de- 

 scribed a new species, C. arctica^ to which he refers a form of C. 

 echlnata from Kara Sea, described by Traustedt. In the two partic- 

 ulars in which the Alaskan specimens differ from the typical villosa 

 they incline toward C. arcttca, for in this species the spines are situ- 

 ated in groups of eight or ten on prominent papillae of the test, and the 

 folds of the sac are seven, or occasionally eight, in number. 



In the number of tentacles, however, the Alaskan form of villosa 

 agrees with the type and not with arctica ; and since, as shown above, 

 neither of its arctica tendencies is pronounced, it must be considered 

 most closely allied to villosa. Perhaps further study of more material 

 will show the necessity of establishing a new species for it ; but as the 

 matter now stands this course is not justifiable. 



There are about fifteen specimens in the collection, all from Yaku- 

 tat Bay, taken on rocks at extreme low tide, June 20-22, 1899. 



