ABYLA TRIGONA. 221 



than its slight anatomical significance would suggest. It is, as noted above, 

 largely on account of the curved somatocyst in the bracts of Abyla leuckartii 

 that I have identified the latter as the young stage of the "Ceratocymba." 



In several examples there are two gonophores. 



A. leuckartii has so far been recorded, in its polygastric state, only from the 

 Indo-Pacific region, where it is widely distributed in warm waters. But that 

 it also occurs in the Atlantic, where it has been generally overlooked, is proved 

 by an excellent and altogether typical specimen which I collected in the West 

 Indies, and which is now in the collection of the Museum of Comparative Zoology. 

 Its occurrence in the West Indies has also been reported to me by Dr. A. G. 

 Mayer. 



Abyla trigona Quoy and Gaimard. 

 Plate 13, figs. 3, 4. 



Abyla trigona Quoy and Gaimard, '27, p. 14, pi. 2B, fig. 1-8; Eschscholtz, '29, p. 131; Blainville, '30, 



p. 123; '34, p. 135, pi. 4, fig. 4; Gegenbaur, '60, p. 337, taf. 26, taf. 27, fig. 9-12; Chun, '88, p. 1160; 



97b, p. 31; Schneider, '98, p. 90; Lens and Van Riemsdijk, .-08, p. 28, pi. 4, fig. 34-36 (non 



Huxley, '59, p. 47, pi. 3, fig. 1). 

 Amphiroa alata Blainville, '30, p. 121; '34, p.'133, pi. 4, fig. 1 (Lesueur, Manuscr.); Huxley, '59, p. 64, 



pi. 5, fig. 1; Chun, '88, p. 1160; '97b,p.31; Lens and Van Riemsdijk, : 08, p. 28, pi. 4, fig. 37, 38. 



EUDOXID. 



Diphyes abyla Quoy and Gaimard, '34, p. 87, pi. 4, fig. 12-17. 



Eudoxia trigonae Gegenbaur, '60, p. 349, taf. 27, fig. 10-12. Eudoxid. 



Abyla carina Haeckel, '88b, p. 156, pi. 35. 



Amphiroa carina Haeckel, '88a, p. 33; '88b, p. 114, pi. 36. Eudoxid. 



Amphiroa trigona Haeckel, '88a, p. 33; '88b, p. 113. Eudoxid. 



The polygastric stage was taken at Stations 4646, 4673, 4684, 4713, 4715; 

 seven entire specimens and two loose anterior nectophores, in both surface and 

 300 fathom hauls. The largest anterior nectophores are about 6 mm. long, the 

 posterior ones 7-13 mm. 



I have been able to compare these very well-preserved specimens with an 

 Atlantic series, with which they agree so closely that I have no doubt of their 

 specific identity. The same conclusion was reached by Lens and Van Riems- 

 dijk for the "Siboga" collection. A. trigona has been so well described by the 

 various authors listed in its synonymy that no detailed account is called for. 

 The only species of the genus with which it might be confused is ^4. haeckeli 

 Lens and Van Riemsdijk, and the presence of a single ventral facet in the superior 

 nectophore of trigona (Plate 13, fig. 4) instead of two ventral facets as in haeckeli 

 (Plate 13, fig. 2) readily separates the two. For a detailed account of the facets 

 and ridges, see Lens and Van Riemsdijk, : 08, p. 29. The posterior nectophores 

 agree very well with the accounts by Gegenbaur ('60) and by Haeckel ('88b). 



