68 CURRENT LITERATURE. 



Stearns. R. E. C— The Fossil Freshwater Shells of the Colorado Desert, 



their distribution, environment and variation. Proc. U.S. Xat. Mus., 



1901, vol. .xxiv, pp. 271 — 299, pis. xix — xxiv. 



To all interested in the distribution and variation of the mollusca. Dr. 



Stearns' paper presents numerous points worthy of consideration, while the 



six beautifully clear plates, make the paper an exceedingly valuable one. 



Stanton, T. W.—CIioi!drodoiiia,a new genus of ostreiform mollusks from the 

 Cretaceous, with descriptions of the genotype and a new species. Ibid., 

 pp. 301 — 307, pis. XXV, xxvi. 

 Dr. Stanton is of opinion that the 'Osfrea iniinsoui, Hill, is not a member of 



the genus Osirca nor referable to any described genus, he therefore proposes 



the name Chondrodouta as a new genus for this and a new species, C. glabra. 



The affinities of the new genus seem to be with the Pectinacca, which includes 



the Spondylidac. Limidac and Pcctinidac. 



Williamson, M. Burton.— a Monograph on Pccku acquisiikaiiis. Cpr. Bull. 

 S. Calif. Ac. Sci., 1902, vol. i, no. 5, pp. 51 — 61, pi. iv — vi. 

 Mrs. M. Burton Williamson gives an interesting account of this mollusc, 

 and some notes on the various parts of its anatom\'. The paper scarcely deserves 

 the title of monograph, but we hope the authoress will later give us a more 

 detailed account of the anatomy, including the nervous system, illustrated by 

 clearer figures, 



MoUendorff, 0. von. — Binnen-MoUusken aus Westchina und Centralasien. 



II. L'Ann. du Mus. Zool. d I'Acad. Imp. Sci. St. Pctersb., 1901 (1902), 



T. vi, pp. 299 — 412, Tafn. xii — xvii. 



Continuing his work on the Mollusca of Western China and Central Asia, 



the author here devotes the greater portion to the genus Bnliiiiiiius, of which 



he describes and figures upwards of 40 new species and a dozen sub-species. 



The following new subgenera -are described : — Piipiiiidiiis ftype B. piipiiiidiiis 



ii.sf.J, Pciraconiasitis (typeB. ]iciideaiiiis,Aiicty,)Claiisiliopsis f'type B.szccliciiyi, 



Bttg.), Lopliaiiclicn (t} pe B. crisiaiclliis, n. sp.), Coccodcrvia (type B. graiiiilaiiis, 



Mdff.). Two new sub-species of Piipilla, 2 species of Pliacdiisa, and i of 



Liinuaca are also described. 



Randies, W- B. — ^.'erestic variation in Tivchus zizyphiniis. Nature, 1902, vol. 

 65, P- 535, figs- 1,2. 

 The author records and figures the presence of two supernumerary eyes 

 on the ri^ht ocular tentacle. So far as could be made out from the examina- 

 tion of an incomplete series of longitudinal seclions, all the eyes seem to have 

 been functional during life, each being provided with ciyslalline Itn?, retina 

 and optic nerve. The innervation is derived from a single optic nerve arising 

 from the right cerebral ganglion. This nerve bifurcates, one branch passing 

 to the primary eye, and the other again dividing, supplies the two secondary 

 eyes. 



Kew, H. 'Wallis.— On the Mucus-threads of Land-Slugs. Journ. Conch., 

 1901, vol. 10, pp. 92—103. 4 figs ; 1902, vol. II, pp. 153 — 165, 3 figs. 

 Mr. Kew gives a very useful resume of the published observations upon 

 this subject, together witti some observations of his own, and others communi- 

 cated by correspondents. 



