On the Nauplius and Pupa Stage of Suctoria. 233 



Head exserted, perpendicular j face swollen between the eyes; 

 carina raised, linear, and extending downwards on the surface 

 of the trigonate clypeus in the form of a longitudinal ridge ; 

 encarpge transverse, contiguous, separated from the front by a 

 deep transverse groove ; eyes distant, oval ; antennaj with the 

 three lower joints pale piceous, the rest black. Thorax twice 

 as broad as long ; sides reflexed, slightly rounded, nearly 

 parallel, the anterior angles produced, very obtuse ; upper 

 surface impressed at the base with a broad transverse groove, 

 which extends on either side nearly to the lateral margin ; 

 surface minutely granulose, coarsely punctured, the punctures 

 crowded on the basal groove, more scattered over the disk. 

 Scutellum trigonate. Elytra much broader than the thorax, 

 convex, transversely excavated below the basilar space, the 

 latter distinctly thickened, the humeral callus also thickened ; 

 surface closely and rather coarsely punctured, bright metallic 

 green with a bluish tint, the apex fulvous. 



Much broader and more ovate than the other known 

 species. 



To the Editors of the Annals and Magazine of Natural History. 



XXVI. — On the Nauplius and Pupa Stage of Suctoria. 

 By Prof. Alfred Giard. 

 Gentlemen, — 



In the July number of the ' Annals ' Mr. C. Spence Bate 

 published an interesting paper " On the Naujdius Stage of 

 Prawns." In this he attempts to prove that the Naujylius 

 described by Fritz Miiller as belonging to Penoius cannot be 

 the young of any prawn, but appears to be the larva of a 

 Schizopod more or less related to Euphausia^ or of one of 

 the Suctorian parasites. 



As far as Metschnikoff's observations enable us to decide, 

 the Nauplius stage is, in fact, the earliest form of the larval 

 condition of Euphausia^ whilst most of the Schizopods (the 

 Mysis group for example) present a condensed development. 

 It may be also fairly assumed that this important Navplius 

 stage may be more frequent amongst tlie Schizopods than 

 amongst the prawns, the latter occupying a higher rank in tlie 

 class and offering a Mysis stage in their ontogenic evolution. , 



I cannot, however, admit that the opinion suggested by Mr. 

 Spence Bate, viz. that Mltller's larvaj belong to a Schizopod, is 

 established on solid observations or on serious arguments ; but 

 I am absolutely sure this Nauplius cannot be related to any 

 form of the Suctoria. Lilljeborg and Anderson have long ago 



Ann. tC- Mag. N Hist. Ser. 5.' Vol ii. 16 



