NOTE ON A NEW BRITISH ECHIUROID GEPHYREAN. 379 



neighbouring genera Thalassema and Bonellia. He dis- 

 covered and figured the minute worm-like male living as a 

 parasite in the dilated pharynx of the female Hamingia. 

 Lankester regards Hamingia as having a closer resemblance 

 to Bonellia in internal organs, and to Thalassema in ex- 

 ternal characters ; while it is quite peculiar in having the 

 genital pores on prominent papillae, and in the absence of 

 genital setae in the female. He gives a useful tabular state- 

 ment of the characters of the three genera, which I shall make 

 use ®f in discussing the position of our new form. 



The specimens I am describing from the Irish Sea are inter- 

 mediate in their characters between the genera Thalassema 

 and Hamingia as defined by Lankester, but in my opinion 

 they come nearer to Thalassema — so near, in fact, that I 

 think they must constitute a species of that genus. I shall 

 take up the characters seriatim as given by Lankester in 

 his tabular statement,^ 



1. In shape of body the new form agrees equally well with 

 Hamingia (since Lankester showed that that form possessed 

 a large proboscis, as long as the body) and with various species 

 of Thalassema. It perhaps most nearly resembles in size 

 and shape the T. gigas of M. Miiller, from the Adriatic. 



2. The proboscis agrees equally with the characters of the 

 two genera. 



3. The female genital pores in Hamingia are one or two 

 in number, and open on well-marked papillae. In Thalassema 

 (according to Lankester) the female genital pores are four to 

 six, and are not placed on papillae. In our new form there 

 are no papillae, but only two pores are present. In this 

 character, then, our form is intermediate between the two 

 genera. In Thalassema gigas and T. faex, however, there 

 is said to be only one pair of "segmental organs'^ (see Greef 

 Selenka, and K. Lampert), and therefore, I take it, only one 

 pair of female apertures. I should alter, then, this character - 



> 'Ann. and Mag. N. H.,' vol. xi, 1883, p. 42. 



' This extension of the diagnosis is recognised by Rietsch, Selenka, and 

 others. 



