664 MR. J. GRAHAM. KERR ON THE [Juue 18, 



7. On some Points in the Anatomy of Nautilus pompilius. 

 By J. Graham Kerr, Christ's College, Cambridge. 



[Eeceived June 17, 189.5.] 

 (Plates XXXVIII. & XXXIX.) 



I. Introduction, p. (i64. 

 II. The Body-cavity of Nautilus, 



p. 664. 

 III. The Male Genital Ducts and 



Penis, p. 671. 

 IV. The Buccal Nervous System, 



p. 673. 

 V. The Innervation of the " Inner 



Inferior Lobe," p. 675. 

 VI. The Post-anal Papillae and 

 Neryes, p. 676. 



VII. The Spermatophore-receiving 



Apparatus, p. 677. 

 VIII. The Morphology of the " Arms" 

 of Cephalopods, p. 678. 

 IX. The Phylogenetic Eelationships 

 of the Cephalopoda, p. 683. 

 X. Summary of Conclusions, 

 p. 685. 

 Explanation of the Plates, 

 p. 689. 



I. Introduction. 



During the year 1893 Mr. Adam Sedgwick very generously 

 placed at my disposal a number of specimens of Nautilus pompili^is 

 with the suggestion that I should make an examination of their 

 structure. The specimens were twenty-five in number, of which, 

 however, the great majority were very young and immature. 

 Owing to the method of preservation and to several months' sojourn 

 in saw'dust moistened with spii'it, the condition of the specimens 

 was usually such as to render them unfit for histological study. 

 Fortunately one of them was sufficiently good to allow the use of 

 the section -method to confirm the results of minute dissection. In 

 the following somewhat fragmentary paper it is my purpose to 

 touch upon what seem to me the more important points at which 1 

 have arrived, hoping at some future date, if able to obtain properly 

 preserved specimens, to extend my investigations and to fill up the 

 obvious lacunae. 



I can hardly adequately express the obligation under which I am 

 to Mr. Sedgwick for the generous gift by which he has made these 

 investigations possible and opened the way to what, however poor 

 its results are so far, has proved a study of absorbing interest, and 

 also for much kind advice and encouragement. To Mr. Wilson 

 also a wovA. of thanks is due for the care with which he has attended 

 to the illustrations. 



II. The Body-cavity of Nautilus. 



It is now generally recognized that the body-cavity in the 

 higher Metazoa may be referred to either of two very distinct types. 

 The first of these, typically developed in Annelida and Vertebrata, 

 is lined by a definite characteristic epithelium, from some of whose 

 cells arise the genital products, while others become the renal 

 excretory cells. It appears at an early stage in development .as a 

 more or less continuous space, and it communicates with the 



