736 



II. SPECIAL CONTRIBUTION. 



With Plates LXXV.— LXXXIIL, a Map, and 15 Text-figures. 



This is neither the time nor the opportunity for the composition of a costly 

 monograph on Nautilus. It will be time when the embryonic stages have been 

 discovered and opportunity when it is possible for an investigator to command the 

 requisite knowledge and material to permit of detailed comparisons being made, step 

 by step, between more or less distantly related types. I am only able to furnish 

 a contribution which partakes of the nature of a monograph in a strictly limited 

 sense of the term. The new matter contained in these pages consists of facts and 

 suggestions some of which have been already published in a preliminary form, and 

 relates principally to the following aspects of the subject: — bionomics (habits, range, 

 oviposition), branchial sense-organs (osphradia), mechanism of respiration, injection of the 

 vascular system, connections of the siphuncle, innervation of the ophthalmic tentacles, 

 development of the accessory sexual organs, enumeration of the digital tentacles, 

 orientation, and specific divergence. 



1. Historical Survey. 



The bibliography of Nautilus includes so many memoirs of the first order of 

 importance written at varying intervals by experienced anatomists of different schools 

 and countries during the last seventy years, as to convey the impression that its 

 conchological, malacological and biological properties must be well-nigh established and 

 that the only scope for further contributions to knowledge must take the direction of 

 physiological and embryological researches. Such however is not the case, and so far 

 as the finer anatomy and oecology of Nautilus are concerned, it will be long before 

 the Pierian spring is exhausted. 



The seven decades which have elapsed since Nautilus was assigned its definite 

 position in the natural system fall into two very distinct periods, the first of which 

 was inaugurated by Sir Richard Owen 1 in 1832, followed by Valenciennes 2 in 1841, 

 and terminated by Keferstein 3 in 1865. The second period, which is now in course, 



1 Owen, R., " Memoir on the Pearly Nautilus." Published for the Council of the Royal College of Surgeons, 

 1832, with 8 plates. 



2 Valenciennes, A., " Nouvelles recherches sur le Nautile flambe (Nautilus pompilius, Lam.)." Arch. Mus. 

 Paris, ii. pp. 257—314, PI. vin— xi, 1841. 



3 Keferstein, W., "Beitriige zur Anatomie des Nautilus pompilius." Nadir. Ges. Gottingen, 1865, pp. 355 — 

 375 ; plates published in Bronn's Klassen und Ordnungen des Thierreichs, 1866, in illustration of Malacozoa- 

 Cephalopoda, Taf. ex — oxv. 



