CEPHALOPODA. 



555 



Organ of Touch. With respect to the sense 

 of touch, the exposed part of the integument 

 of the Nautilus presents numerous papillary 

 eminences ; and several of the naked Cepha- 

 lopods are remarkable for the irregular surface 

 of the skin, which seems designed to increase 

 its natural sensibility. Thus, in the Cranchia 

 scabra, flattened processes terminating in nu- 

 merous pointed denticulations, project from 

 the surface of the mantle ; in the Sepia papil- 

 lata the integument is beset with branched 

 papillae ; in Sepia mammillata with more sim- 

 ple obtuse eminences; in Sepia tuberculata, 

 with tubercles; in Octopus aculeatus, with 

 pointed tubercles, &c. That these projections 

 serve to warn the creature of the nature of the 

 surfaces which come in contact with its 

 body is highly probable; and it is not at all 

 uncommon to find in those species, which have 

 smooth skins over the body generally, that 

 there are tubercles in the immediate neigh- 

 bourhood of the eyes, as in the Octopus 

 vulgaris, Octopus Lichtenaultii, Octopus Wes- 

 terniensis, &c. 



In the Nautilus, the more exposed pedun- 

 culate eyes are expressly provided with re- 

 tractile sensitive tentacles on each side, as has 

 been already mentioned. 



With respect to the organs destined for the 

 active exercise of touch or exploration, we 

 must suppose that the numerous tentacles with 

 which the Nautilus is so remarkably provided, 

 from the softness of their texture, their an- 

 nulated surface, and liberal supply of nerves, 

 serve in this capacity as well as instruments of 

 prehension and locomotion. The less nu- 

 merous but more highly developed arms of 



Fig. 237. 



the Dibranchiates doubtless exercise the same 

 faculty, especially at their attenuated flexile 

 extremities. 



The internal fringed circular lip surrounding 

 the mandibles, in both orders of Cephalopods, 

 presents another example of the dermal co- 

 vering so disposed as to be the seat of delicate 

 sensation. 



GENERATIVE SYSTEM. The individuals of 

 the present class are, as before stated, of distinct 

 sexes, which in the Dibranchiate order are re- 

 cognizable by diversity of size, external form, 

 colour and shape of the internal rudimental 

 shell. In the common Calamary, for example, 

 the glad ius of the male is one-fourth shorter, 

 but broader than that of the female. 



As only the female organs are known in the 

 Tetrabranchiate order, we are limited in the 

 description of the male parts, to those which 

 exist in the Dibranchiate Cephalopods; but 

 from the close resemblance subsisting in the 

 two orders in the form of the organs of the 

 female sex, little difference can be expected to 

 exist in the structure of the male apparatus. 



In the Poulp the male organs consist of a 

 testicle, a vas deferens, a kind of vesicula 

 seminalis, a gland compared by Cuvier to the 

 prostate, the sac containing the moveable fila- 

 ments which Needham's description rendered 

 so celebrated, and lastly the penis. 



The testicle is situated at the bottom of the 

 visceral sac, and is composed of a membra- 

 nous pouch (a, Jig. 237), to one part of the 

 inner surface of which are attached a number 

 of branched elongated glandular filaments (&), 

 which swell at the breeding season, and dis- 

 charge an opake white fecundating fluid into 

 the sac. From this cavity the fluid escapes 

 by the orifice (c), and passes into the vas de- 

 ferens (d). This is a narrow tube, indefinitely 

 convoluted upon itself; it opens into another 

 larger canal (e), the interior of which is di- 

 vided by ridges and incomplete septa; its 

 texture seems to be muscular, so that it pro- 

 bably serves by its contractions to eject the 

 fluid carried into it by the vas deferens. From 

 the vesicula seminalis the semen next traverses 

 the extremity of an oblong gland (f), which 

 is of a compact granular structure, and, like the 

 prostatic or Cowperian glands, contributes some 

 necessary secretion to the fecundating fluid. 



Next follows the muscular pouch (g) con- 

 taining the filaments or animalcules of Need- 

 ham (A). When first exposed, they present 

 the appearance of white filaments, from six to 

 eight lines in length, packed closely and regu- 

 larly in parallel order, in three or four rows 

 one above another, from the fundus to the 

 aperture of the pouch ; and they are kept in 

 that position by a spiral fold of the membrane 

 of the pouch, without, however, having the 

 slightest adhesion to that part. For a long 

 time after being removed from their position 

 they continue to exhibit, when moistened, 

 motions of inflection in different directions. 

 A short and narrow canal (i) leads from the 

 pouch to the root of the penis (/c), which is 

 a short pyramidal body, hollow within, and 

 terminating by a small anterior aperture, 



2o2 



