ZOOLOGY. 699 



the more probable, (1) that the same species of shell is developed by three 

 family types which otherwise have the hard and soft parts duly co- 

 ordinated, or (2) that the animals have been dissociated from their own 

 shells, and in some way or other been thrust into shells of Marginella 

 glabella. If the alleged facts of Dr. Carriere were established, no cer- 

 tainty could be enjoyed in either morphology or palaeontology. It is 

 noteworthy, finally, that there is no co-ordination between the opercula 

 or animals of the pseudomarginellse and the shells. 



CEPHALOPODS. 



General. 



Blake (J. F.) A Monograph of the British Fossil Cephalopoda. Part I. Introduc- 

 tion and Silurian Species. With 31 pi. London, Van Voorst, 1882. (4°. 244 pp.) 



Brock (J.) Ziir Anatomie imd Systematik der Cephalopoden. Mit 4 Taf. Zeitschr^ 

 f. wiss. Zool., V. 36, pp. 543-610. 



Fischer (Paul). Sur la classification des C^phalapodes. Jonru. de conchyliol., v. 30, 

 pp. 55-57. 



Maurice (Charles). Expos^ des recherches de M. W. Branco sur I'embryog^nie et lea 

 affinit^s des c^phalopodes fossiles. 2 partie. Lille. Ann. Soc. G6ol. du Nord, 

 V. 9,pp. 104-125. 



Steenstrup (Japetus). Notse teuthologicse. Oversigt k. Danske Videusk. Selsk. 

 Forhandl., 1882, pp. 143-168. 



Digestion. 



Borquelot (Em.) Eecherches exp6rimentales suar Taction des sacs digestifs des Ceph- 

 alopodes sur les matiferes amyloc^es et sucr^es. Archiv. Zool. Experiment., v. 10, 

 pp. 385-422. 



Ink-bag. 



Girod (P.) Recherches sur la pochc dn noir des c^phalopodes des cdtes de France 

 Av6c 5 pi. Archiv. Zool. Exp^rim., 1. 10, pp. 1-100 ; Abstr. in Journ. R. Microsc. 

 Soc. London (2), v. 2, pp. 487-489. 



The major groups of Cephalopods. 



The Cephalopods are of peculiar interest on account of the intense 

 morphological specialization of the members, their range in time and 

 space, and the geological history of the group. Within a short period 

 much has been contributed to a better understanding of the class by 

 Messrs. A. Hyatt, Munier-Chalmas, Broch, Paul Fischer, and especially 

 A. E. Verrill. The taxonomic rank of the Cephalopods as a class may 

 be considered to be established and undisputed, and equally certain is 

 it that all the living forms are perfectly segregable into two primary sec- 

 tions of the value of orders at least. These groups were first correctly 

 defined and named Tetrabranchiata and Dibranchiata by Professor 

 Owen in 1838, but were earlier recognized and denominated Tentaculi- 

 feres and Ac^tabuliferes by Ferussac and d'Orbigny in 1834. But there 

 are numerous extinct Cephalopods as to whose affinities there are still 

 some doubts. For a long time they were supposed to be closely related 

 to the Xautilids, and consequently to be Tetrabranchiates ; such are 

 the Ammonites and kindred forms. But Professor Agassiz nearly twenty 



