II 
between Valentia in Ireland and the Farée banks, and gave a characteristic figure. This genus is 
distinguished from Cad/anus, by the presence of a remarkable hook on the anterior surface of 
the second joint of the basiopodite of the first feet, and by the last joint of the exopodites of 
the second, third, and fourth feet being furnished with three spines on the outer margin, instead 
of two as in Ca/anus. \WOLFENDEN fully described his genus in 1905, in Plankton Studies, part 1. 
Sars in the same year (1905a) described a very similar form under the name of Macrocalanus 
longicornis, and a good deal of confusion arose through no figures accompanying the description. 
Sars, however, in 1907 (4), withdrew his genus in favour of the one named by WoLFENDEN, which 
had the prior claim. WoLrFeNpeEN in his first description had then only met with one form, to 
which he gave the name Megacalanus princeps. In Plankton Studies, part I, the number of species 
under J/egacalanus was increased to two. The specific name przxzceps originally adopted for the 
type of the genus was dropped in favour of a new specific name, éradyz, while the name przuceps 
was applied to the additional form, which is clearly not a MZegacalanus. There is no doubt, 
that Megacalanus bradyi is the same form for which the genus was founded in 1904, as it is 
characterised by the prominent hook on the second basal joint of the first feet and the figure 2, 
plate I, is identical with the figure given with the original description in 1904. The second 
species of the genus, was identified as equal to Brapy’s Calanus princeps of the Challenger 
report, and the basiopodite of the first pair of feet is described as having no trace of hooks. 
In the interval between the publication of WoLFENDEN’s two papers Sars had recorded 
the occurrence of Macrocalanus princeps (Calanus princeps Brady). 
In Plankton Studies, part I], 1906, Worrenpen has the following note: “Professor G. O. 
“Sars has informed me that the genus Megacalanus (Wolfenden) is identical with his genus 
“ Macrocalanus (Sars) (Bull. du Musée Océanog. de Monaco), and Megacalanus Bradyi is the 
“same as his species Wacrocalanus longicornis, and that my name, Megacalanus, however has 
“the priority over JJacrocalanus. He also informs me that the species described by me as 
“Megacalanus princeps = Calanus princeps (Brady) is not that species, but = Lathycalanus 
“Richardt (G. O. Sars), and that Brapy’s Calanus princeps is a true Megacalanus, differing 
“from MW. longicornis (G. O.S.) = Megacal. Bradyi (Wolfenden), in the strongly recurved frontal 
“appendages, somewhat shorter Anterior Antennae, and the dense ciliation of the spines on the 
“Anterior Maxillipedes, which otherwise are quite normal in appearance. 
“The genus Bathycalanus differs from MJegacalanus in the peculiar armature of the 
“frontal part and in the somewhat different structure of the maxillae and maxillipedes (both 
“pairs), and in the structure of the first pair of feet, which are without the hooked process of 
“the second basal, and have the outer ramus composed of only two joints’. 
It is quite certain that Wo.LFENpEN’s second species, Megacalanus princeps (Brady), 1s 
not a Lathycalanus, because WOLFENDEN in his description of the species states that the first 
four pairs of feet have three-jointed rami. WoLFENDEN, after an examination of the dissections 
of Calanus princeps preserved in the British Museum, concludes that BRrapy’s species is neither 
a Megacalanus nor a Bathycalanus, yet he finally renames AZegacalanus princeps Wolfenden, 
not the original one which established the genus in 1904, as Bathycalanus maximus. 
SARS 1905(@), and Farran 1908, identify Brapy’s Calanus princeps with the genus 
at 
