l82 



CURRENT LITERATURE. 



Pilsbry, Henry A. — Tryon's Manual of Conchology, ser. ii, vol. xiii (pt. 51), pp. 

 113 — 176, pis. 35—48. Philadelphia: Academy of Natural Sciences. 



The Fiji species of Placostyhis are here completed, and the subgenus Diplo- 

 mor[i}ia, Anc, treated of. P. cuxiana. New Hebricles, is a new species. The author 

 then gives a series of descriptions, previously omitted, of various Australian Bulinioid 

 Hclicidac. 



The larger portion of the present part is devoted to the genus Amjihidro7)U(s, 

 Alb. Dr. rilsbry concludes from the researches of Semper, Wiegmann and Jacobi, 

 that the genus does not belong to the Buliimdidac, but to the E/'liiphal/ugunK group 

 of the Hclicidac. The genus is a difficult one, and will probably remain so for some 

 time to come, in fact until our knowledge of the specific anatomical characters is 

 more complete. Dr. Pilsbry groups the species in 20 groups, agreeing in part with 

 those of Fulton. Seven of these groups are dealt with in the present part, and 

 keys to the shell-characters are given in most cases. — W. E. C. 



Bergrh, R. — Ergebnisse einer Reise nach dem Pacific (Schauinsland 1896 — 1897). 

 Die Opi.sthobranchier. Zool. Jahrb. (Abth. f. Syst.) 1900, Bd. 13, pp. 207 — 

 246, T. 19—21. 



Dr. P)ergh here describes the Opisthobranchs collected by Prof. Schauinsland in 

 1896 — 97. The new forms are O/u/idoniira liirundinina, Q. and G., v. c/cga/is, 

 Bgh. (n.?sp. ), Archiduris xydca, Aculidicllci clrusUla, A. faiistiiia, and Samla 

 annuligcra, n. g. et sp. The new genus belongs to the Flabcllinidae, and is charac- 

 terised by the beautiful perfoliate rhinophoria, a rounded anterior margin to the 

 foot, a triseriate radula, with a denticulate anterior margin to the lateral teeth, and 

 an unarmed penis. — VV. E. C. 



Smith, J. Perrin. — Larval Stages of ScJducnbachia. Journ. Morph., 1S99, vol. 

 xvi, pp. 237 — 268, pis. A — E. 



Mr. Perrin Smith continues his very valuable studies on the ontogeny of the 

 Ammonites. A short time ago he gave a very careful account of the development 

 of the genera Lytoccras and J'/n/loccras, and in tlie present paper the larval stages of 

 Schlocnbachia orcgoncnsis are dealt with. The species is a remarkable one, in that 

 its descent is so very clearly shown through its ontogeny. In its development it 

 repeats in the first five septa the history of Anarcestes, Parodoceras, and Priono- 

 ceras ; then for about a single whorl it is a Glyphioceras ; in the next one and a 

 quarter a Gcislrioecras ; then for a little more than one-quarter of a revolution 

 a Paralogoccras, the goniatite history terminating at two and five-eighths coils. It 

 now develops a keel, and resembles one of the simpler Permian and Lower Triassic 

 ammonites. Then follow the ananeanic, metaneanic, and paraneanic stages. With 

 the appearance of the sixth whorl, the shell commences to take on its own proper 

 characters, and is then in the ephebic stage. Thus it will be seen, the larval stages. 

 may be compared with Paleozoic genera. This interesting form offers a striking 

 illustration of the law of the acceleration of development. 



With the advance of the stage, the author finds that there is a great increase in 

 the individual variation, this being still greater with the acquirement of adult char- 

 acters, so that were, it not for the transitions between the varieties, one would feel 

 inclined to make several species out of one. — W. E. C. 



Smith, J. Perrin. — The Development and Phylogeny of Placcnliccras. Proc. 

 Cal. Acad. Sci. (3rd ser.). Geology, 1900, vol. i, pp. 181 — 240, pis. xxiv — 

 xxviii. 



This paper is prefaced by an interesting " Introduction " on the law of tachy- 

 genesis. The author then devotes a section to a discussion upon the affinities of 

 Placenticcras and Hoplites and gives a phylogenic table of P/acenticeras and asso- 

 ciated genera, which must both prove of value to all students of fossil Cephalopoda. 



