26 
THE VOYAGE OF H.M.S. CHALLENGER. 
Lesson. In this it will be observed that the branchial plume extends right round the 
posterior side of the nucleus just as depicted in Lesson’s original figure, 1 in d’Orbigny’s 
representation of Cardiopoda pedunculata, 2 and also as in the only specimen in the 
Challenger collection. These four I am inclined to regard as females of the same species. 
Undoubted male Cardiopoda? have been figured by Eydoux and Souleyet, 3 by d’Orbigny, 4 
and by Macdonald. 5 The figure of Cardiopoda caudina given by Rang 6 also I believe 
represents a male. In each instance it will be noticed that the branchiae are on the 
anterior side of the nucleus, and as in the case of the females I think it very probable 
that only one species exists. If this opinion be correct the species known as Cardiopoda 
caudina and Cardiopoda carinata are the male, and those named Cardiopoda placenta 
and Cardiopoda pedunculata the females, of one and the same species. 
The specimen obtained by the Challenger was captured off Arrou Island on 
September 23, 1874. It is about 77 mm. in length, and has at the slender caudal 
extremity a small dentate sucker not nearly so large as that represented by Eydoux and 
Souleyet in their figure of Cardiopoda placenta. The tail is strengthened by muscular 
bands on each side as in the species of Car inaria, and the sucker on the ventral fin is 
very minute and somewhat behind the centre. It is very likely that the suckers in 
females will be found to be smaller than in the males, as has been shown to be the case in 
the species of the genus Pterotrachea. Besides this apparently adult example, six very 
small specimens representing the early stages of growth of Cardiopoda were obtained in 
the North Pacific on July 4, 1875. These are not all alike, but exhibit certain variations 
which may be due to difference of age or sex, but not any of them are precisely like the 
figures of the young as represented by Macdonald and Souleyet. 
1 Voy. “ Coquille,” pi. iii. fig. 2. 
2 Voy. Amer. merid., pi. xi. fig. 5. 
3 See Cardiopoda caudina, Voy. “ Bonite,” pi. xvii. fig. 11. 
4 Cardiopoda carinata, Voy. Amer. merid., pi. xi. fig. 4. 
5 Trans. Roy. Soc. Edin., 1862, vol. xxiii. pi. i. fig. 10. 
6 Mag. Zool., 1832, pi. v. 
