REPORT ON THE MYZOSTOMIDA. S" 



both exactly corresponded in form and colour with figs. 7 and 8 on pi. ii. of the Keport, 

 except that there was here no trace of the dorsal median depression. 



The larger of the two individuals was doubly deformed ; for in the first place the 

 first left parapodium was reduced to a very small prominence, and secondly it bore, 

 between the seventh and eighth left cirri, a small supernumerary cirrus (fig. 4, c). 



12. Myzostoma testudo, Grafi". 



Myzostoma testudo, GrafE, Bull. Mus. Comp. Zool. Cambridge, vol. xi. p. 128, 1883. 



15. Myzostoma marginatum, Graff. 



Myzostoma mwginatum, Graff, Ihid. 



16. Myzostoma brevipes, Grafi". 



Myzostoma brevipes, Graff, Ihid., p. 127. 



17. Myzostoma carpenteri, Graff. 



Myzostoma carpenteri, Gratf, Proc. Roy. Soc. Edin., vol. xii. p. 380, 1884. 

 „ „ Nansen, Op. cit. 



Since the Report was published Dr. Carpenter has discovered that the host of this 

 species, Antedon sarsii of the Scandinavian naturalists ( = Alectro dentata, Say), is 

 identical with the Asterias tenella of Retzius ; and it must therefore be known in future 

 as Antedon teyiella, Retzius sp. 



18. Myzostoma areolatum, Graff. 



Myzostoma areolatum, Graff, P)iill. Mus. Comp. Zobl. Cambridge, vol. xi. p. 127, 1883. 



20. Myzostoma coriaceum, Graff. 



In the collection of the K. zool. Genootschap in Amsterdam, I found on a black 

 Actinometra (n. sp.), from the Moluccas, a specimen of the above. It measured 8 mm. 

 in diameter, and agreed in every respect with the specimen described in the Report 

 (pi. xi.). The latter was found, however, on an Antedon^ {Antedon insignis), the 



1 The generic difference in the liost of Myzostoma coriaceimi is a fm-ther proof of the correctnes,s of a criticism 

 made by Dr. P. Herbert Carpenter, who write.s to me as follows : — "I notice that you say on page 21 (Report) ' where one 

 species infests more tliat one host, tlie latter are always closely allied.' This does not always hold good, as tlie genus 

 is sometimes different, e.g., Myn. echinus, elecjans, carinatum, inflator, and costatum, while Ant. eschrichtii and Ant. 

 carinata, on which Myz. gigas is found, are very different indeed ; so also Ant. hageni and Ant. spinifera (hosts of 

 Myz. agassizi). I fancy that in many cases, e.g., Myz. tenuispinain, it is rather a question of locality." 



