360 



38. Parra gymnostoma. Wagler. 

 Tigre Island. 



39. Dendrocygna autumnalis (L.). 

 " Lake of Yojoa." 



5. On the Genus Synapta. By S. P. Woodward and Lucas 

 Barrett. (Communicated by J. S. Gaskoin, Esq.) 



(Radiata, PI. XIV.) 



The marine animals allied to the Sea Cucumbers, forming the 

 genus Synapta, possess a peculiar interest for that large class of 

 persons who study Natural History with the microscope, because 

 they afford the miniature Anchors, of which a hundred may be 

 shown in the field of the "inch object-glass," and thousands some- 

 times exist in the space of a square inch — each elegant in form and 

 perfectly finished, and articulated to an anchor-plate whose pattern 

 (as well as that of the anchor itself) is characteristic of the species 

 to which it belongs. 



Curiously enough, these anchors were unknown to all the earlier 

 writers, and most of the moderns. Forskal, who had the merit of 

 describing two species of Synapta so long ago as 17/5, remarked 

 that they " adhered to the finger by glutinous papillae invisible to 

 the eye." O. F. Miiller called the Northern species Holothuria in- 

 hcerens for the same reason. And Eschscholtz, who met with several 

 species at Tahiti and on the coast of Russian America, concluded 

 that they ought " to form a class apart, not having tubular feet, but 

 adhering, by means of their sharp skin, to extraneous objects, on 

 which account they might be called Synapta *." 



Only five years ago (in 1863) Mr. Cocks of Falmouth described 

 two British species, and gave a magnified figure of the skin without 

 seeing the anchors. And still more recently Mr. Gosse was unable 

 to find them, even with the aid of a microscope f. However, they 

 are present in all the examples that have come under our notice, and 

 they can always be seen with a common pocket lens. Indeed the 

 larger anchors of Synapta digitata are nearly half a line in length, 

 and visible to the unassisted eye. 



Jaeger says that all the anchors of his Synapta Besehi are ird of 

 a line in length, and can be seen without a glass. This great Synapta 



* Appendix to Kotzebue's Second Voyage, 8vo, Lond. 1830, p. 338. Van der 

 Hoevcn makes Eschscholtz say the Synapta adheres " by means of small hook- 

 lets ; " but this expression (der sie uberall wie Kletten anhangen) is employed in 

 the introductory paragraph. In the special description of Synapta he only speaks 

 of " small roughnesses (Rauhigkeiten) invisible to the naked eye." And he de- 

 scribes Chiridota verrucosa as, " corpore undique verrucis rubris adhaerentibus 

 obsito."— Zool. Atlas, fol. Berlin, 1829. 



t Aquarium, p. 243. 



