70 PKOCEEDrNGS OF THE MALACOLOGICAL SOCIETY. 



Prof. E,, Semon cMring his recent sojoiirn in Australia and tlie Malay 

 Archipelago. As a result of the excellent preservation of Semen's 

 specimens, Haller has been enabled to describe several interesting 

 points in histological detail. 



Following close upon these papers is a preliminary report on 

 a critical study of the Nautilus from Australia, by Professor Haswell 

 of the Sydney University ; and when we consider that he of necessity 

 commands ample material, and that some of the recent descriptions of 

 the parts of this animal are grossly misleading by error of orientation, 

 we await the full report of so trustworthy an observer with eagerness. 

 Special interest attaches to Professor HasAvell's work, in its bearings 

 on the question of sexual differences in the tentacular lobes. 



This naturally leads us to a recognition of the attempt now 

 being made by Willey to work out the development of this archaic 

 creature — an attempt which we know to have been rewarded ' by the 

 capture of young specimens, through the adoption of a lobster-pot 

 method, akin to that long ago successfiilly employed and recommended 

 for use in deep water by Dr. Giinther.^ 



D'Orbigny, as is well known, more than fifty years ago suggested 

 that certain differences in the shells of Ammonites might possibly be 

 indicative of sexual dimorphism. The first important conclusion put 

 forward by Willey is, that in the adults of the Nautilus pompilius 

 this is the case ; and the interest of the observation is heightened 

 by its confirmation a month later by Vayssiere, with extension to 

 N. macromphalus. 



Intimately related to this topic is that of the determination of the 

 inter-relationships of the hordes of extinct Cephalopoda — alas ! known 

 to us only by their shells. To mention the name of Hyatt in this 

 connection is to command respect. AVithin a month of my predecessor's 

 address to you, Hyatt had eclipsed himself. Dealing ' with the dorsal 

 furrow or "impressed zone" from a developmental standpoint, in an 

 important monograph laid before the American Philosophical Society 

 in August, 1894, he has sought to establish a case for "the phylogeny 

 of an acquired characteristic " which little short of a refutation of his 

 determinations would appear to me to weaken — and the glove is once 

 more thrown down on behalf of the palaeontologists, but by one of 

 their number who happens to be also an embiyologist. 



That vexatious organ the aptychus has during the year yielded 

 a point of supreme interest, Dr. li. Michael, of Breslau, having 

 discovered* a Solenhofen slab bearing an Oppelia steraspis, within 

 the body-chamber of which there lie the remains of some sixty 

 shells of the offspring, each with its own aptychus. From the 

 detailed study of the specimen the conclusion has been drawn that 



1 Willev, Nat. Sci., vol. vi, p. 409. 



~ Giinther, "Instructions for collecting Eeptiles, rjntrncliians, and Fishes" for 

 Erit. Mus. Nat. Hist. Lond. 1891, p. 15, primarily in Auleitung z. Wiss. 

 Bobachtungen auf Reisen, Berlin, 1880, p. 423. 



■* Proc. Araer. Phil. Soc, vol. xxxii, p. 349. 



* Zeitschr. Deutseh. Geol. Gesell., Bd. xlvi, p. 697. 



