two new Species o/' Hectocotyle. 17 



or whether they are to be regarded as animals quite different, and belonging 

 perhaps to the class of Epizoa. According to my conviction the first is the 

 correct view, which I hope best to prove by showing how I myself arrived at 

 this conclusion. 



After I had concluded the anatomical examination of the two Hectocotylce, 

 I for the first time entertained doubts of their relation to Epizootic worms, 

 as for example Tristoma and Myzostoma, which they so perfectly resemble in 

 their outward appearance, when I considered that not one of these wortns, 

 although not unfrequently provided with a highly developed vascular system, 

 possesses two kinds of vessels, that is to say, arteries and veins, a heart and 

 branchiae. Yet this alone, as may easily be believed, would not have been suf- 

 ficient to induce an opposite conclusion, if other facts had not attracted my 

 attention and compelled me to examine more carefully. In the first place, I 

 was compelled to recognize the remarkable similarity of the Hectocotylce fur- 

 nished with numerous suckers and violet pigment-spots with the arms of the 

 Cephalopods on which they live ; a similarity which extends so far that the 

 suckers of Hect. Argonautce, with reference to the form and arrangement of 

 the muscles, perfectly resemble those of the Argonaut, while those of the 

 Hect. Tremoctopodis accurately represent those of the Tremoctopus ; and the 

 colour of the pigment-spots in each of the two animals belonging to each 

 other perfectly coincided. Continuing to meditate on the subject, I called 

 to mind several other points of agreement. First, the spermatozoa of Hec- 

 tocotyle, which (like those of Sepia, Octopus, &c.) are furnished with a mode- 

 rately long cylindrical body and a long filiform appendage; and secondly, 

 the contractile pigment-cells, which occur in Hectocotyle exactly as in the 

 Cephalopods, which is the more important, inasmuch as these remarkable 

 cells have hitherto been found in no other animals. Lastly, I discovered the 

 interesting fact, that the fibres which form the muscular mass of the arms of 

 the Cephalopods are arranged in exactly the same complicated manner in 

 three layers as those which form the muscular envelope of the body of the 

 Hectocotylce. 



All these facts at length led to the conviction that there existed a remark- 

 able agreement between the Hectocotylce and their Cephalopods ; and the 

 more I considered the subject, the more I felt compelled to believe in a cer- 



VOL. XX. D 



