I 





Prof. E. Ray Lankester on Hamingia arctic*. 39 



outside the harbour, south of the lighthouse island. The spot 

 was nearly the same as that where, two years previously, 

 Mr. Norman had dredged u a Bonellia-Yiko, Gephyrean," 



which he has had the great kindness to place in my hands 

 for examination since our return to England. This specimen 

 also proves to be a Hamingia. 



Proboscis or Frontal Hood. — At first sight I was inclined 

 to suppose that the Gephyrean dredged this summer was not 

 Hamingia, but a Thalassema. It was about half the size of 

 Koren's and Danielssen's specimen, of a bright apple-green 

 colour, and had a long contractile proboscis resembling closely 

 that of Thalassema and Echiurus. The proboscis, when ex- 

 tended, was as long as the body, each measuring about an inch 

 and a half in length when thus extended. As is shown above, 

 Koren and Danielssen have made the absence of a proboscis 

 or frontal hood a leading character of their genus Hamingia. 

 Dr. Horst describes one of his specimens as possessing a rudi- 

 mentary proboscis. As is well known, the proboscis or frontal 

 hood is very readily broken away in Echiurus ; and its absence 

 has before now led to erroneous conclusions. Quite recently 

 Sluiter has shown that Sternaspis is normally provided with a 

 large bilobed frontal lobe corresponding to the proboscis of 

 Echiurus , though it has been broken off in every specimen 

 hitherto described, and its existence not even suspected. 



Shape of Body. — The movements of the body and its altera- 

 tions of form in the living state closely resembled the move- 

 ments and changes of shape of Thalassema neptuni, Gartner, 

 which I have observed in large numbers on the coast of Devon- 

 shire. Indeed I should have concluded from the examination 

 of external characters that the specimen was a green-coloured 

 Thalassema, differing only from other Thalassemce in the 

 absence of genital setce. 



Uterine Pouches and Ova. — On dissection, however, the 

 identity of our specimen with Hamingia became quite certain. 

 In place of the four or six uterine sacs present in Thalassema 

 there was a single pair present, having very delicate transpa- 

 rent walls, unlike those of Thalassema. The ova and the 

 ovaries were unlike those of Thalassema, and presented the same 

 peculiarities as those of Bonellia, and thus corresponded with 

 the description of Koren and Danielssen. 



Cloacal Trees. — Further the u cloacal trees," or " nephri- 

 dia," were found to differ from the simple pouches which 

 occur in Thalassema, and to agree with those of Bonellia in 

 being branched, as described and figured by Koren and 

 Danielssen in their specimen. 



Red Corpuscles of Ccelom, — One important fact I was able 



