CIRRHOPODA. 



691 



of the process which forms a kind of caudal 

 prolongation of the abdomen (t', t'). This 

 canal runs to the distal extremity, and opens 

 by a minute orifice fringed with very fine hairs. 

 In Otion Cuvieri the two canals are continued 

 distinct to the very point of the process, where 

 there are two openings.* The walls of the 

 organ, which we have compared to the seminal 

 vesicle, have a glandular structure, which 

 Cuvier imagined to be the testicle. The re- 

 searches of Professor Burmeister have led him 

 to the same conclusion. He says it can be no- 

 thing but the testicle.f Cuvier, as well as 

 Lamarck, regarded what we have called the 

 testicle as the ovary, and believed that the ova 

 were impregnated, in the course of their passage 

 along the oviducts, by the seminal fluid flowing 

 from the testicle investing these canals. The 

 granular lobules of the true testicle, which were 

 supposed to be immature ova, are found always 

 in the same state, and what are more distinctly 

 ova are found within the peduncle. J 



The lengthened tubular process (f, t',fig. 

 344), through which the excretory duct of the 

 testicle passes, is articulated ; the margin of 

 each joint is fringed with minute hairs. In 

 Otion and Coronula, Burmeister found large 

 canals closed at both extremities, within the 

 process, in addition to the ducts from the testi- 

 cle. This organ is generally found after death 

 bent upwards on the abdominal surface ; but, 

 during life, it is in continual motion. Its use 

 is, probably, to carry the seminal fluid back- 

 wards beyond the current caused by the move- 

 ments of the arms, in the event of there being 

 mutual impregnation between separate indivi- 

 duals ; or towards the mouths of certain ducts 

 which communicate with the ovary within the 

 peduncle, in case of self-impregnation taking 

 place. In this view it must be regarded as 

 the penis ; and it is so called by the most 

 recent authors on the subject Wagner and 

 Burmeister. Mr. Thompson calls it an ovipo- 

 sitor ; and conjectures that, after their expul- 

 sion from the ovary, (understanding by this 

 what we regard as the testicle,) the eggs are 

 conveyed by it into the cellular texture of the 

 pedicle. How they pass from this depository 

 into the general cavity, where they afterwards 

 form two or three foliated groups, he confesses 

 himself unable to explain. 



The pedunc'e of the Lepads was formerly 

 regarded merely as an organ of support, and 

 even Cuvier discovered within it nothing but 

 what appeared to him to be a homogeneous 

 pulp, surrounded by muscular tissue. But, at 

 certain seasons of the year, at least, there are, 

 very distinctly developed, throughout the greater 

 part of the soft matter which constitutes the 

 bulk of the organ contained within the dense 

 cartilaginous and muscular tunics, certain oval 

 granules, regular, and uniform in shape, and 

 gradually increasing in size. Poli and Lamarck 



* Burrneister, Beitrage, p. 46. 



t Op. cit. p. 44. 



t Professor Wagner is satisfied that nothing but 

 the discovery of spermatic animalcules can assure 

 us against error in our attempts to determine what 

 is the testicle. 



were of opinion that these were truly eggs, but 

 held that they were originally formed in the 

 granular organ surrounding the intestine, (now 

 regarded as the testicle,) and merely deposited 

 here temporarily. But the recent researches of 

 Professor Wagner and M. St. Ange have ren- 

 dered it probable that it is the ovary which is 

 contained within the peduncle. The organ in 

 question seems to occupy the whole of the pe- 

 duncle within the layers of muscular tissue. 

 It is separated from the visceral cavity by a 

 fine membrane which lines that cavity, and is a 

 reflexion of the mantle. A transverse section 

 of the ovary shews the eggs most fully deve- 

 loped towards the outer margin, and scarcely 

 formed in the centre. There are also seen in 

 the same section two canals which run longitu- 

 dinally through the organ, one near that side 

 of the margin which corresponds to the anterior 

 aspect of the body of the animal, the other in a 

 similar situation on the dorsal aspect. Of these 

 canals, the anterior is the larger ; and it alone 

 was described by Cuvier, who regarded it as 

 connected with the circulating system. The 

 other was first described by M . St. Ange, who 

 satisfied himself that it is a true oviduct. In 

 Anatifa, he traced it pursuing a straight course 

 through the ovary, and leaving it as a perfect 

 canal just at the posterior and inferior angle of 

 the organ, thence passing on the outer surface 

 of the lining of the visceral cavity, in the groove 

 of the dorsal valve, and terminating in an orifice 

 opening into the visceral cavity not far from the 

 brachial slit.* We have found a structure 

 exactly resembling the above in Otion, where, 

 however, instead of opening into the general 

 cavity of the visceral sac, the duct is bifurcated 

 just between the two auriform appendages, into 

 each of which one of the branches of the duct 

 enters and opens. M. St. Ange found eggs 

 in progress through this duct; and they are 

 frequently found, arranged in groups or packets, 

 two or three in number, within the cavity of 

 the mantle. We have not yet seen them in the 

 duct ; but the whole structure of the parts in 

 question seems to indicate their adaptation to 

 the function assigned to them by M. St. Ange. 

 Tins being the case with regard to Anatifa, it 

 appears to be very probable that the use of the 

 singular auriform appendages in Otion is to 

 afford a convenient lodging for the eggs before 

 the young are hatched. Their deep sinuosities 

 and folds seem to adapt them admirably to 

 this purpose. Packets of eggs, however, are 

 found within the cavity of the mantle in this 

 species as in others. According to Burmeister, 

 these packets are unattached, excepting in the 

 earliest stage of development ; but Wagner has 

 generally found them fixed to a process of the 

 mantle, situated near the adductor muscle of 



* Professor Wagner says, " at the base of the 

 dorsal valve there exists a slit in the mantle which 

 leads into the canal that runs through the peduncle. 

 I presume that this canal serves as an oviduct, and 

 that the slit is analogous to the opening of the 

 branchial canal in the bivalves," (in Archiv fur 

 Anat. Physiol. &c. von D. J. iMiiller, 1834, No. 5, 

 quoted in Ann. des Sc. Nat. iv. n. s.) We are not 

 aware what species was anatomized by Professor 

 Wagnrr. 



