446 W. F. LANCHESTER. 



1796, Herbst. Figure very poor. Text: — "Das letzte Glied hat solcher Erhohungen drey, 

 und einen breiten, platten. Rand der durch Einschnitte viermal geziihnt ist." (Italics mine.) 

 Corresponds with my variety F below. 



1837, M. -Edwards. Text: — " Abdomen... son dernier article surmonte de six gros tubercules 

 along^s et son dernier segment... portant trois ou cinq tubercules along^s tr^s arrondies, et 

 arm^ de dents marginales courtes, larges, et renfl^es." (Italics mine.) The presence of " three 

 or five " tubercles on the telson is interesting as showing that Milne-Edwards had before 

 him examples both of var. F mihi and var. glah-ous Brooks (or var. graphurus Miers) and 

 yet did not distinguish them as species; in fact he adds, at the end of his description, 

 and after giving a long list of localities to show the world-wide distribution of the species, 

 " du moins je n'ai pu d^couvrir aucune particularite constante pour distinguer entre eux les 

 individus venants de ces parages eloignes." The absence of any mention of the ' anchor,' 

 and the fact of the ridges being very swollen (tres arrondies) renders it probable, though 

 not absolutely certain, that his forms with three ridges correspond with my var. F. 



1852, Dana. The lateral marginal teeth and the anchor are not shown in the figure. 

 Corresponds to var. F. 



1865, Heller. A small specimen, 20 mm. long, badly preserved. Text : — " Das letzte 

 Segment dreieckig, stark gewolbt, in der Mitte mit einen scharf Langskiele versehen, der nach 

 riickwarts mit einem kleineiii Stachel endet, nach beiden Seiten hin dachformig, glatt ; die 

 Rander jederseits mit drei Ziihnen bewaffnet." (Italics mine.) The presence of only one 

 ridge is due to the small size of the .specimen, without doubt; although the lateral ridges 

 are generally visible even in smaller specimens than Heller's, they are sometimes obscure 

 (or possibly absent) in individuals of 20 mm., though this is not usual. The sharpne.ss of 

 the median keel, its termination in a spine, and the presence of lateral marginal teeth point 

 to the specimen being a young var. smithii. 



1872, von Martens. Pointed out evidence of considerable variation in the presence or 

 absence of spines. It is not apj^arent which variety his specimens correspond to. 



1880, Miers. In this his well-known work " On the Squillidae " Miers has given a full 

 description of our species: the only points which concern us are in regard to the telson, 

 which in his forms has three swollen spineless carinae, the middle one without an anchor 

 and no lateral marginal teeth. For two reasons in particular I have chosen this as the type, 

 firstly, because it is the form of Herbst who described the species shortly after Fabricius, and 

 also the form of the great majority of authors after him ; and secondly, because it is the 

 form from which most of the varieties with which I shall deal appear to have taken their 

 origin. Dr de Man in 1898 selected the spineless anchor-form as the type, but he gave no 

 reason for so doing, and it is extremely improbable that Fabricius' types corresponded to 

 this form at all : anyhow in the absence of evidence as to Fabricius' types we are justified 

 in taking Herbst's form as the type of the species. The type then corresponds with my 

 variety F. 



1886, Brooks, and 1893, Henderson. Follow Miers. 1894, Bigelow. In his key to the 

 species of Gonodactylus Bigelow makes it quite clear that his G. chiragra is identical with 

 the type. 1898, de Man. His type form corresponds with my variety incipiens b = var. A. 

 1900, Borradaile. Has followed de Man. I have adhered to the system of lettering intro- 

 duced by him, so that his var. A and mine correspond, as do the rest of the varieties lettered 

 by him. 



