444 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



the tip. (7) The structure of the third legs is radically different from 

 that of the Caliginse and similar to that of the Pandarinae (p. 29). 



These reasons are well stated and convincing, but unfortunately 

 Hesse made such serious blunders, both morphological and physio- 

 logical, in this same paper that they have virtually annulled the force 

 of his systematic argument. Some of these errors have already been 

 discussed elsewhere.'^ It is sufficient to state here that Hesse describes 

 his " Nogagus spina cii-achantias'' as a female, with the male unknown. 

 His attempt, therefore, to establish a female Nogaus is the third in 

 chronological order. His only apparent reason for considering his 

 specimen a female is the fact that he found a chalimus embryo 

 attached to its carapace. 



He accordingly assumes that the adult is the mother and the chali- 

 mus is her offspring. 



Both the description and the figures which Hesse gives show that 

 the adult is a male and not a female, and in all probability it is the 

 male of ''Pandarus spinacii-acliantias,'' which Hesse obtained from 

 the same fish and in company with the " Nogagus'' (see p. 458). 



The fourth attempt to find a Nogaus female was the publication by 

 Beneden in 1892 of the two sexes of " Nogagus angustatus.'' Beneden 

 states that he considei's this the same as Gerstaecker's " Nogagus 

 angustulus,'' the male of which was published in 1854. The difference 

 in the spelling of the two species names is accounted for by a printer's 

 error in Gerstaecker's paper. In the text the name appears as arigus- 

 tulus, but in the explanation of the plates it is changed to angustatus. 

 But Beneden also made two mistakes here; in the first place the male 

 of his species is quite different from that described by Gerstaeker, 

 (ft) in the relative size of the carapace, {b) in the fusion of the second 

 and third thorax segments, which are entirely distinct in Gerstaecker's 

 male, (r) in the size and more especially the shape of the genital seg- 

 ment, (.d) in the abdomen, one-jointed and very short in Beneden's 

 specimen, but two-jointed and two-thirds as long as the genital seg- 

 ment in Gerstaecker's species (see pp. 351 and 431). 



The second error was in naming the female from the male ; if Bene- 

 den's figure of the female is at all accurate, it belongs to the genus 

 Nesippus. And hence his male becomes a male Nesippus instead of 

 the female becoming a female Nogaus. 



This latter genus is therefore left as it was at the beginning, without 

 a single female representative of any of the species. Indeed, the only 

 female which could possibly bear the genus name Nogaus would be 

 the female of Leach's original type Nogaus latreillii. But this female 

 is now found to be the form described by Leach in the same paper on 

 the preceding page under the name Pandarus cranchii. This genus 



"Proc. U. S. Nat. Mus., XXVIII, pp. 547-548. 



