26 BULLETIN 60, UNITED STATES NATIONAL MUSEUM. 



ee. Umbo of carinal latu8 at the lower third of the oarinal border. 



N. portoricannm. 

 dd. Capitulum widest in the middle, tapering to the base; inframedian latns 



erect ,S. lomjicarlnainni. 



cc. Upper end of the inframedian latus obtuse or truncate. Paciiic species. 



d. Rostrum present ,S'. sanctipetreme. 



dd. Rostrum wanting. 



e. Plates fully calcified; umbo of inframedian latus subapical. 



.S'. (jruveUanum. 

 ee. Plates separated by wide chitinous sutures; umbo of inframedian latus 



submedian ,S'. grureUanuni secundum. 



III). Inframedian latus of very irregular shape, its upper carinal angle produced; 

 roof of carina deeply guttered, 

 c. Scales of the peduncle minute, 0.2 to 0.3 mm. wide; scutum and upper latus 



radially striate; carina narrow. East coast of Patagonia S. ratliJmme. 



cc. Scales of the peduncle about 1 mm. wide; scutum and upper latus not radi- 

 ally striate; carina wider. Galapagos iS. soror. 



aaaa. Carinal latus subtriangular, its narrower umbonal half free, projecting downr 

 ward below the carina, umbo terminal. 

 h. Carina with wide intraparietes, the umbo not apical; inframedian latus oblong- 

 pentagonal, the umbo not apical. Gulf of Mexico *S'. arietinum. 



hb. Carina with narrow sides throughout, the umbo terminal; inframediarr latus 

 triangular, with the apex curved toward the scutum, umbo apical. 



S. dlceraluin. 



GROUP OF SCALPELLUM VELUTINUM. 



The carinal latus has a recurved umbo, either apical or near the 

 upper border of the plate; the triangular inframedian latus is wider 

 than high; the capitulum is more or less thickly clothed with a velvetj^ 

 cuticle. Large or very larg'e forms. 



This group comprises most of the largest species of the g-enus known. 



SCALPELLUM VELUTINUM Hoek. 

 Plate III, tig. 2, 3. 



1883. Scalpellum relutinum Hoek, Challenger Rep., Cirripedia, p. 96, pi. iv, tigs. 



10, 11. Off Cape St. Vincent, 900 fathoms, and off Tristan da Cunha 1,425 



fathoms. — Gruvel, Exped. Sci. du Travailleur et du Talisman, Cirrhij)edes, 



1902, pp. 56, 136, pi. Ill, fig. 1; pi. xi, fig. 3c. Off Cape Cantin, Cape Moga- 



dor, Fuere venture and Pilones, in 882 to 2,000 meters. 

 1883. Scalpellum exhn'mm Hoek, Challenger Rep., Cirripedia, p. 100, pi. iv, figs. 



6, 7. Off Tristan da Cunha, 1,000 fathoms. 

 1898. Scalpellum sordidiun Aurivillius, Bull. Soc. Zool. de France, XXIIJ, j). 



190. 

 1902. Scalpellum alalitm Gruvel, in Exped. Sci. du Travailleur et du Talisman, 



Cirrhipedes, p. 57. 



