bo 



In adult female cephalothorax transversely expanded, 

 connected by a very narrow, smooth, cylindrical " neck " with 

 a large and smooth, somewhat bulb-like genital segment, 

 which carries behind two large clusters of tubules and two 

 long and narrow ovisacs ; the mouth very small, and apart 

 from its obscure constituents no appendages present on the 

 head or trunk. Male unknown. Young with eight pairs of 

 appendages. 



The generic name is obviously derived from <T(pvpioi'^ a little 

 hammer. Cuvier, founding the genus upon the "■Choiidracaiithe 

 lisse " of Quoy and Gaimard, defines Sphyrion as having 

 " la tete elargie des deux cotes, comme un marteau, de petits 

 crochets a la bouche, un cou mince, suivi d'un corps deprim^ 

 et en forme de coeur, qui, outre les deux longs cordons, 

 porte de chaque cote un gros faisceau de poils." There is 

 little fault to be found with this definition, except that the 

 word " poils " is inappropriate to the blunt-ended, often bifid 

 and trifid, branchlets, which in two great bunches are 

 appended to the genital segment, probably with a branchial 

 function. 



Sphyrion laevigatum, Guerin-Meneville. 

 Plate 4. 



1824. Chondracanthc lisse, Quoy et Gaimard, in Freycinet's 



Voyage autour du Monde, Zoologie, Atlas, pi. 86, 



fig"- 10. 

 1830. Sphyrion lissc, Cuvier, Le Regne Animal, Zoophytes 



(Intestinaux cavitaires), vol. 3, p. 257. 

 1829-43. Sphyrion laevigatus^ Guerin-Meneville, Iconographie 



du Regne Animal, Zoophytes, p. 11, pi. g, fig. 4. 

 1840. Sphyrion la ev I gatus,y[S\xiQ,-Y.6.-^dLxd.^, Hist. nat. des 



Crustaces, vol. 3, p. 526. 

 1836-49. '^Sphyrion levigatus, Cuv." Le Regne Animal, Edit. 



illustree. Zoophytes (Intestinaux, Cavitaires), p. 



62,63, pi. 32, fig. 4, 4a. 

 1869. Sphyrio7i laevis, Steenstrup, Oversigt Vidensk. selsk. 



Kjdbenhavn, p. 202, pi. 2, fig. 4a, 4b. 

 1890. Lesteira kroyeri, G. M. Thomson, Trans. New Zealand 



Institute, vol. 22, p. 370, pi. 28, f. 4, 4a. 

 1899. Sphyrion laevigahon, Bassett-Smith, Pr. Zool. Soc, 



London, p. 489. 



The soft cephalothorax which is wholly embedded in the 

 tissues of the host is in this species distinguished by its great 

 width, being not as in Sphyrion lu?npi (Kroyer) narrower, but 

 much wider than the genital segment. It is also very 

 nodulose and somewhat variably so, the extremities in 

 Thomson's New Zealand specimen being simply rounded, 



