148 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



with the just mentioned glands upon the mantle of the female. Their strueture is certainly very 

 much like that of the glands described by Kerr. As the epithelium of the inner surface of the 

 mantle had been rul)hed off in my specimens, I can not say anything about its structure. It is 

 strange that Willey should have overlooked the ciliated surfaces described by Kerk. Iverr's 

 observation certainly weakens Willey's "final proof regarding the osphradial nature of certain 

 papillae, for this is proof that other regions of the l)ody, aside from the surfaces of the grooves 

 of the ocular tentacles and the interbranchial pajjiihe and the preanal papilhe. are ciliated. The 

 glandular ai'ea is differently developed in different females of various ages, and this I take to be 

 an indication that it forms an accessory part of the female reproducti\e apparatus. 



Let us now sum up the ol)servations on the pallial complex. The mantle is continuous around 

 the body, forming a broad ventral fold fastened along its edge to the edge of the shell, and a 

 small free dorsal fold, connected by very narrow lateral portions. In conformity with this struc- 

 ture there is a capacious ventral mantle cavity containing all the organs collectively forming the 

 pallial complex, and a small dorsal mantle cavity; the two are connected by shallow lateral cavities. 



The pallial complex consists of the following parts: The anus; two pairs of gills; two pairs 

 of nephridial pores; one pair of pericardial pores; two interbranchial and two preanal papilhe, 

 which may be osphradia, coi'responding metamerically to the gills; one pair of reproductive 

 apertures; in the female, the nidamental gland. 



All these parts of the pallial complex, except the reproductive apertures, are .situated upon 

 the inner side of the mantle. The latter are situated upon the body -wall. The renal sacs -also 

 might be considered as forming parts of the pallial complex, for they are situated ■■within the 

 base of the mantle. 



This arrangement of the parts of the pallial complex of Nautilus is very interesting when 

 t^ompared with the Dibranchiata, in which all the organs mentioned are located upon the body 

 wall. The arrangement of the organs of the pallial complex of Nautilus is the same as in many 

 Gastropoda. 



FUNNEL. 



The funnel is an organ of great size, not to be overlooked in the most casual glance at the 

 aninval. While showing a general similarity to the fuimel of the Dibranchiata, it also presents 

 differences of the utmost interest to the student of comi)arative anatomy. Lying closely pressed 

 against the ventral side of the head and nuchal regions, it has a length of alioutS centimeters and 

 a breadth of -t centinu^ters. (Figs. 3. 4, and 6.) The width of the fuimel varies greatly in pre- 

 served specimens, depending largely upon the state of contraction of the organ. It forms an 

 extremely solid mass of tissue. Its posterior end extends well into the mantle cavity. The 

 anterior end lies partly in the ventral groove of the cephalic sheath, and its tip extends a very 

 little beyond the posterior border of the ventral notch of the cephalic .sheath. (Figs. 7, 2-4, 

 and 25.) The funnel forms a long cylinder, but instead of being closed^ like the funnel of the 

 Dibranchiata, it is open upon the ventral side, where its edges merely overlap each other. It is 

 as if the edges of a flat, oblong piece of tissue had been inrolled about the longitudinal axis until 

 their edges slightly overlapped. A better illustration, and one which expresses the commonly 

 accepted morphological idea, is to suppose the edges of the foot of a gastropod to be inrolled 

 toward the ventral side, and al)out the longitudinal axis. 



The partly closed funnel of Nautilus presents, therefore, in the adult condition a form which 

 is found in the embryonic stages only of the Dibranchiata. 



.\t the posterior end of the funnel the sides separate and pass upward over the sides of the 

 nuchal region of the body, just behind the auricles of the hood, forming the crura of the funnel, 

 to the dorsal edges of the shell nuisdes. (Fig. ti, CR.) The dor.sal ends of the crura are 

 united by a thin crescentic ridge rumiing around the posterior excavated side of the hood. 

 (Figs. .5 and 7, CR. ) 



Only the posterior portion of the funnel is attached to the body. The anterior tive-eighths 

 projects completely free fi'om the body, al)le to move in any direction. If we examine the inside 

 of the funnel, we shall get a logical means of separating the anterior and posterior j)ortions of 



