MACRURA. SCII MITT. 319 



Genus PENMSOPSIS, Bate. 



Penvropsis (A. Milne Edwards, M.S.) Bate, Ann. Mag. 

 Xat. Hist. (5), viii., 1881, p. 182 (P. serratus A. 

 Milne EdAvards, M.S.). Id. Kemp, Mem. Indian 

 Museum, v., 3, 1915, p. 320. Id. A. Milne Edwards 

 and Bouvier, Mem. Mus. Comp. Zool., xxvii., 3, 1909, 

 p. 220. 



? Mctai>cn(rus Wood-Mason, Ann. Mag. Nat. Hist. (6) 

 viii., 1891, p. 271 (Pen-cm* fiffinis H. Milne Edwards). 



Though Bate's definition of Pencropsis (A. Milne 

 Edwards, MS.) is worthless, as noted by Kemp (loc. cit.), 

 his citation of an existing type "P. serratus (A. Milne 

 Edwards, MS.), length about 4 inches," 4 together with 

 Milne Edwards's and Bouvier's subsequent careful 

 description of that type, must be accepted as validating 

 the name. But I am not entirely satisfied that Penceopxix 

 Bate and Metapenccus Wood-Mason, are synonymous as 

 is stated by Kemp. There seems to be a small 

 ""P. serratus" group of species within the genus 

 Pencropsis in its broader sense, having characters which, 

 if constant, may separate them from the rest of the 

 "Metapenei." These characters, as exhibited by various 

 species, are discussed in the following pages. 



As Milne Edwards and Bouvier believe Parapencsus 

 mega-lops Smith 5 to be the same as Penceopsis serratus, 

 Smith's types have been carefully re-examined. Prof. 

 Smith failed to mention the peculiar modification of the 

 basal portion of the inner anteunular flagelluin of the 

 male. This forms a flattened semicircular loop ending 

 distally in a more or less backwardly directed blunt knob 

 or tubercle, which is the butt of the straight, distal 

 portion of the flagelluin ; this loop is about one-fourth 

 or fifth of the total length of the flagellum. A very 

 similar structural modification exists in Parapenceus 

 rectacutus (Bate) as figured by Alcock, only Smith's 

 species has the loop annulated like the rest of the 

 flagellum, and not unsegmented as is shown in Alcock's 

 figure. 



1 The type locality is wrongly given as "Gulf of Mexico," 

 probably as a result of a misapprehension as to the scene of the 

 "Blake's" operations. 



5 Proc. U.S. Nat. Mus., viii,, 1885, p. 172. 



"Cat. Indian Decapod Crust., 1906, pt. iii., fasc. i., pi. vi., fig. 19. 



